JAL-3453 Some tests require different Desktop constructor
[jalview.git] / src / jalview / gui / Desktop.java
index 5ee9150..91e1948 100644 (file)
  */
 package jalview.gui;
 
-import static jalview.util.UrlConstants.SEQUENCE_ID;
-
 import jalview.api.AlignViewportI;
 import jalview.api.AlignmentViewPanel;
+import jalview.api.StructureSelectionManagerProvider;
+import jalview.bin.ApplicationSingletonProvider;
+import jalview.bin.ApplicationSingletonProvider.ApplicationSingletonI;
 import jalview.bin.Cache;
 import jalview.bin.Jalview;
+import jalview.gui.ImageExporter.ImageWriterI;
+import jalview.io.BackupFiles;
 import jalview.io.DataSourceType;
 import jalview.io.FileFormat;
 import jalview.io.FileFormatException;
 import jalview.io.FileFormatI;
 import jalview.io.FileFormats;
 import jalview.io.FileLoader;
+import jalview.io.FormatAdapter;
 import jalview.io.IdentifyFile;
 import jalview.io.JalviewFileChooser;
 import jalview.io.JalviewFileView;
+import jalview.jbgui.GDesktop;
 import jalview.jbgui.GSplitFrame;
 import jalview.jbgui.GStructureViewer;
+import jalview.project.Jalview2XML;
 import jalview.structure.StructureSelectionManager;
 import jalview.urls.IdOrgSettings;
-import jalview.util.ImageMaker;
+import jalview.util.BrowserLauncher;
+import jalview.util.ImageMaker.TYPE;
 import jalview.util.MessageManager;
 import jalview.util.Platform;
 import jalview.util.UrlConstants;
 import jalview.viewmodel.AlignmentViewport;
+import jalview.ws.jws1.Discoverer;
 import jalview.ws.params.ParamManager;
 import jalview.ws.utils.UrlDownloadClient;
 
@@ -68,6 +76,7 @@ import java.awt.dnd.DropTargetEvent;
 import java.awt.dnd.DropTargetListener;
 import java.awt.event.ActionEvent;
 import java.awt.event.ActionListener;
+import java.awt.event.InputEvent;
 import java.awt.event.KeyEvent;
 import java.awt.event.MouseAdapter;
 import java.awt.event.MouseEvent;
@@ -84,17 +93,19 @@ import java.util.ArrayList;
 import java.util.Hashtable;
 import java.util.List;
 import java.util.ListIterator;
-import java.util.StringTokenizer;
 import java.util.Vector;
 import java.util.concurrent.ExecutorService;
 import java.util.concurrent.Executors;
 import java.util.concurrent.Semaphore;
 
 import javax.swing.AbstractAction;
+import javax.swing.Action;
+import javax.swing.ActionMap;
 import javax.swing.Box;
 import javax.swing.BoxLayout;
 import javax.swing.DefaultDesktopManager;
 import javax.swing.DesktopManager;
+import javax.swing.InputMap;
 import javax.swing.JButton;
 import javax.swing.JCheckBox;
 import javax.swing.JComboBox;
@@ -107,6 +118,7 @@ import javax.swing.JMenuItem;
 import javax.swing.JPanel;
 import javax.swing.JPopupMenu;
 import javax.swing.JProgressBar;
+import javax.swing.JTextField;
 import javax.swing.KeyStroke;
 import javax.swing.SwingUtilities;
 import javax.swing.event.HyperlinkEvent;
@@ -116,6 +128,8 @@ import javax.swing.event.InternalFrameEvent;
 import javax.swing.event.MenuEvent;
 import javax.swing.event.MenuListener;
 
+import org.stackoverflowusers.file.WindowsShortcut;
+
 /**
  * Jalview Desktop
  * 
@@ -123,26 +137,28 @@ import javax.swing.event.MenuListener;
  * @author $author$
  * @version $Revision: 1.155 $
  */
-public class Desktop extends jalview.jbgui.GDesktop
+@SuppressWarnings("serial")
+public class Desktop extends GDesktop
         implements DropTargetListener, ClipboardOwner, IProgressIndicator,
-        jalview.api.StructureSelectionManagerProvider
+        StructureSelectionManagerProvider, ApplicationSingletonI
 {
-  private static int DEFAULT_MIN_WIDTH = 300;
 
-  private static int DEFAULT_MIN_HEIGHT = 250;
+  private final static int DEFAULT_MIN_WIDTH = 300;
 
-  private static int ALIGN_FRAME_DEFAULT_MIN_WIDTH = 600;
+  private final static int DEFAULT_MIN_HEIGHT = 250;
 
-  private static int ALIGN_FRAME_DEFAULT_MIN_HEIGHT = 70;
+  private final static int ALIGN_FRAME_DEFAULT_MIN_WIDTH = 600;
 
-  private static final String EXPERIMENTAL_FEATURES = "EXPERIMENTAL_FEATURES";
+  private final static int ALIGN_FRAME_DEFAULT_MIN_HEIGHT = 70;
+
+  private final static String EXPERIMENTAL_FEATURES = "EXPERIMENTAL_FEATURES";
 
   private JalviewChangeSupport changeSupport = new JalviewChangeSupport();
 
   /**
    * news reader - null if it was never started.
    */
-  private BlogReader jvnews = null;
+  BlogReader jvnews = null;
 
   private File projectFile;
 
@@ -181,10 +197,17 @@ public class Desktop extends jalview.jbgui.GDesktop
             listener);
   }
 
-  /** Singleton Desktop instance */
-  public static Desktop instance;
+  public static MyDesktopPane getDesktopPane()
+  {
+    Desktop desktop = Desktop.getInstance();
+    return desktop == null ? null : desktop.desktopPane;
+  }
 
-  public static MyDesktopPane desktop;
+  public static StructureSelectionManager getStructureSelectionManager()
+  {
+    return StructureSelectionManager
+            .getStructureSelectionManager(getInstance());
+  }
 
   static int openFrameCount = 0;
 
@@ -192,13 +215,29 @@ public class Desktop extends jalview.jbgui.GDesktop
 
   static final int yOffset = 30;
 
-  public static jalview.ws.jws1.Discoverer discoverer;
+  public Discoverer discoverer;
 
-  public static Object[] jalviewClipboard;
+  public Object[] jalviewClipboard;
 
-  public static boolean internalCopy = false;
+  public boolean internalCopy = false;
 
-  static int fileLoadingCount = 0;
+  private static int fileLoadingCount = 0;
+
+  public JInternalFrame conservationSlider;
+
+  public JInternalFrame PIDSlider;
+
+  /**
+   * just an instance (for testng, probably); no actual frames
+   * 
+   * This flag, when set true, allows a headless-like operation, with a Desktop
+   * object but no actual frames. Though not headless, this option disallows
+   * dialogs to run in test environments.
+   * 
+   * It is set by invoking Desktop.getInstanceOnly().
+   * 
+   */
+  boolean instanceOnly;
 
   class MyDesktopManager implements DesktopManager
   {
@@ -219,7 +258,7 @@ public class Desktop extends jalview.jbgui.GDesktop
       } catch (NullPointerException npe)
       {
         Point p = getMousePosition();
-        instance.showPasteMenu(p.x, p.y);
+        showPasteMenu(p.x, p.y);
       }
     }
 
@@ -267,14 +306,14 @@ public class Desktop extends jalview.jbgui.GDesktop
     public void endDraggingFrame(JComponent f)
     {
       delegate.endDraggingFrame(f);
-      desktop.repaint();
+      desktopPane.repaint();
     }
 
     @Override
     public void endResizingFrame(JComponent f)
     {
       delegate.endResizingFrame(f);
-      desktop.repaint();
+      desktopPane.repaint();
     }
 
     @Override
@@ -323,154 +362,226 @@ public class Desktop extends jalview.jbgui.GDesktop
 
   }
 
+  public MyDesktopPane desktopPane;
+
   /**
-   * Creates a new Desktop object.
+   * Answers an 'application scope' singleton instance of this class. Separate
+   * SwingJS 'applets' running in the same browser page will each have a
+   * distinct instance of Desktop.
+   * 
+   * @return
    */
-  public Desktop()
+  public static Desktop getInstance()
   {
-    /**
-     * A note to implementors. It is ESSENTIAL that any activities that might
-     * block are spawned off as threads rather than waited for during this
-     * constructor.
-     */
-    instance = this;
-    doVamsasClientCheck();
-
-    doConfigureStructurePrefs();
-    setTitle("Jalview " + jalview.bin.Cache.getProperty("VERSION"));
-    setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
-    boolean selmemusage = jalview.bin.Cache.getDefault("SHOW_MEMUSAGE",
-            false);
-    boolean showjconsole = jalview.bin.Cache.getDefault("SHOW_JAVA_CONSOLE",
-            false);
-    desktop = new MyDesktopPane(selmemusage);
-    showMemusage.setSelected(selmemusage);
-    desktop.setBackground(Color.white);
-    getContentPane().setLayout(new BorderLayout());
-    // alternate config - have scrollbars - see notes in JAL-153
-    // JScrollPane sp = new JScrollPane();
-    // sp.getViewport().setView(desktop);
-    // getContentPane().add(sp, BorderLayout.CENTER);
-    getContentPane().add(desktop, BorderLayout.CENTER);
-    desktop.setDragMode(JDesktopPane.OUTLINE_DRAG_MODE);
-
-    // This line prevents Windows Look&Feel resizing all new windows to maximum
-    // if previous window was maximised
-    desktop.setDesktopManager(
-            new MyDesktopManager(
-                    (Platform.isWindows() ? new DefaultDesktopManager()
-                            : Platform.isAMac()
-                                    ? new AquaInternalFrameManager(
-                                            desktop.getDesktopManager())
-                                    : desktop.getDesktopManager())));
-
-    Rectangle dims = getLastKnownDimensions("");
-    if (dims != null)
-    {
-      setBounds(dims);
-    }
-    else
+    return Jalview.isHeadlessMode() ? null
+            : (Desktop) ApplicationSingletonProvider
+                    .getInstance(Desktop.class);
+  }
+
+  /**
+   * For TestNG, this constructor can be utilized to allow the creation of a
+   * singleton Desktop instance with the creation of frames, but no addition to
+   * the Desktop object, as in headless mode. Dialogs are not initiated.
+   * Cache.log is also initialized for some tests that require it despite there
+   * being no Desktop.
+   * 
+   */
+  public static Desktop getInstanceOnly()
+  {
+    Desktop d = (Desktop) ApplicationSingletonProvider
+            .getInstance(Desktop.class);
+    d.instanceOnly = true;
+    return d;
+  }
+  
+  /**
+   * Private constructor enforces singleton pattern. It is called by reflection
+   * from ApplicationSingletonProvider.getInstance().
+   */
+  @SuppressWarnings("unused")
+  private Desktop()
+  {
+    Cache.initLogger();
+    try
     {
-      Dimension screenSize = Toolkit.getDefaultToolkit().getScreenSize();
-      setBounds((screenSize.width - 900) / 2, (screenSize.height - 650) / 2,
-              900, 650);
-    }
-    jconsole = new Console(this, showjconsole);
-    // add essential build information
-    jconsole.setHeader(
-            "Jalview Version: " + jalview.bin.Cache.getProperty("VERSION")
-                    + "\n" + "Jalview Installation: "
-                    + jalview.bin.Cache.getDefault("INSTALLATION",
-                            "unknown")
-                    + "\n" + "Build Date: "
-                    + jalview.bin.Cache.getDefault("BUILD_DATE", "unknown")
-                    + "\n" + "Java version: "
-                    + System.getProperty("java.version") + "\n"
-                    + System.getProperty("os.arch") + " "
-                    + System.getProperty("os.name") + " "
-                    + System.getProperty("os.version"));
+      /**
+       * A note to implementors. It is ESSENTIAL that any activities that might
+       * block are spawned off as threads rather than waited for during this
+       * constructor.
+       */
+      if (!Platform.isJS())
+      {
+        doVamsasClientCheck();
+      }
 
-    showConsole(showjconsole);
+      doConfigureStructurePrefs();
+      setTitle("Jalview " + jalview.bin.Cache.getProperty("VERSION"));
+      setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
+      boolean selmemusage = jalview.bin.Cache.getDefault("SHOW_MEMUSAGE",
+              false);
+      boolean showjconsole = jalview.bin.Cache
+              .getDefault("SHOW_JAVA_CONSOLE", false);
+      desktopPane = new MyDesktopPane(selmemusage);
 
-    showNews.setVisible(false);
+      showMemusage.setSelected(selmemusage);
+      desktopPane.setBackground(Color.white);
+      getContentPane().setLayout(new BorderLayout());
+      // alternate config - have scrollbars - see notes in JAL-153
+      // JScrollPane sp = new JScrollPane();
+      // sp.getViewport().setView(desktop);
+      // getContentPane().add(sp, BorderLayout.CENTER);
 
-    experimentalFeatures.setSelected(showExperimental());
+      // BH 2018 - just an experiment to try unclipped JInternalFrames.
+      if (Platform.isJS())
+      {
+        getRootPane().putClientProperty("swingjs.overflow.hidden", "false");
+      }
 
-    getIdentifiersOrgData();
+      getContentPane().add(desktopPane, BorderLayout.CENTER);
+      desktopPane.setDragMode(JDesktopPane.OUTLINE_DRAG_MODE);
 
-    checkURLLinks();
+      // This line prevents Windows Look&Feel resizing all new windows to
+      // maximum
+      // if previous window was maximised
+      desktopPane.setDesktopManager(new MyDesktopManager(
+              (Platform.isWindowsAndNotJS() ? new DefaultDesktopManager()
+                      : Platform.isAMacAndNotJS()
+                              ? new AquaInternalFrameManager(
+                                      desktopPane.getDesktopManager())
+                              : desktopPane.getDesktopManager())));
 
-    this.addWindowListener(new WindowAdapter()
-    {
-      @Override
-      public void windowClosing(WindowEvent evt)
+      Rectangle dims = getLastKnownDimensions("");
+      if (dims != null)
       {
-        quit();
+        setBounds(dims);
+      }
+      else
+      {
+        Dimension screenSize = Toolkit.getDefaultToolkit().getScreenSize();
+        int xPos = Math.max(5, (screenSize.width - 900) / 2);
+        int yPos = Math.max(5, (screenSize.height - 650) / 2);
+        setBounds(xPos, yPos, 900, 650);
       }
-    });
 
-    MouseAdapter ma;
-    this.addMouseListener(ma = new MouseAdapter()
-    {
-      @Override
-      public void mousePressed(MouseEvent evt)
+      // Note that this next syntax, checking for Platform.isJS and also
+      // escaping the code using @j2sIgnore, serves two purposes. It gives
+      // us an easily findable tag, Platform.isJS(), to places in the code where
+      // there is something different about the SwingJS implementation. Second,
+      // it deletes the unneeded Java-only code form the JavaScript version
+      // completely (@j2sIgnore), since it will never be used there.
+
+      if (!Platform.isJS())
+      /**
+       * Java only
+       * 
+       * @j2sIgnore
+       */
       {
-        if (evt.isPopupTrigger()) // Mac
+
+        jconsole = new Console(this, showjconsole);
+        // add essential build information
+        jconsole.setHeader("Jalview Version: "
+                + jalview.bin.Cache.getProperty("VERSION") + "\n"
+                + "Jalview Installation: "
+                + jalview.bin.Cache.getDefault("INSTALLATION", "unknown")
+                + "\n" + "Build Date: "
+                + jalview.bin.Cache.getDefault("BUILD_DATE", "unknown")
+                + "\n" + "Java version: "
+                + System.getProperty("java.version") + "\n"
+                + System.getProperty("os.arch") + " "
+                + System.getProperty("os.name") + " "
+                + System.getProperty("os.version"));
+
+        showConsole(showjconsole);
+
+        showNews.setVisible(false);
+
+        experimentalFeatures.setSelected(showExperimental());
+
+        getIdentifiersOrgData();
+
+        checkURLLinks();
+
+        // Spawn a thread that shows the splashscreen
+
+        SwingUtilities.invokeLater(new Runnable()
         {
-          showPasteMenu(evt.getX(), evt.getY());
-        }
+          @Override
+          public void run()
+          {
+            new SplashScreen();
+          }
+        });
+
+        // Thread off a new instance of the file chooser - this reduces the time
+        // it
+        // takes to open it later on.
+        new Thread(new Runnable()
+        {
+          @Override
+          public void run()
+          {
+            Cache.log.debug("Filechooser init thread started.");
+            String fileFormat = Cache.getProperty("DEFAULT_FILE_FORMAT");
+            JalviewFileChooser.forRead(Cache.getProperty("LAST_DIRECTORY"),
+                    fileFormat);
+            Cache.log.debug("Filechooser init thread finished.");
+          }
+        }).start();
+        // Add the service change listener
+        changeSupport.addJalviewPropertyChangeListener("services",
+                new PropertyChangeListener()
+                {
+
+                  @Override
+                  public void propertyChange(PropertyChangeEvent evt)
+                  {
+                    Cache.log.debug("Firing service changed event for "
+                            + evt.getNewValue());
+                    JalviewServicesChanged(evt);
+                  }
+
+                });
+
       }
 
-      @Override
-      public void mouseReleased(MouseEvent evt)
+      this.setDropTarget(new java.awt.dnd.DropTarget(desktopPane, this));
+
+      this.addWindowListener(new WindowAdapter()
       {
-        if (evt.isPopupTrigger()) // Windows
+        @Override
+        public void windowClosing(WindowEvent evt)
         {
-          showPasteMenu(evt.getX(), evt.getY());
+          quit();
         }
-      }
-    });
-    desktop.addMouseListener(ma);
+      });
 
-    this.setDropTarget(new java.awt.dnd.DropTarget(desktop, this));
-    // Spawn a thread that shows the splashscreen
-    SwingUtilities.invokeLater(new Runnable()
-    {
-      @Override
-      public void run()
+      MouseAdapter ma;
+      this.addMouseListener(ma = new MouseAdapter()
       {
-        new SplashScreen();
-      }
-    });
+        @Override
+        public void mousePressed(MouseEvent evt)
+        {
+          if (evt.isPopupTrigger()) // Mac
+          {
+            showPasteMenu(evt.getX(), evt.getY());
+          }
+        }
 
-    // Thread off a new instance of the file chooser - this reduces the time it
-    // takes to open it later on.
-    new Thread(new Runnable()
+        @Override
+        public void mouseReleased(MouseEvent evt)
+        {
+          if (evt.isPopupTrigger()) // Windows
+          {
+            showPasteMenu(evt.getX(), evt.getY());
+          }
+        }
+      });
+      desktopPane.addMouseListener(ma);
+    } catch (Throwable t)
     {
-      @Override
-      public void run()
-      {
-        Cache.log.debug("Filechooser init thread started.");
-        String fileFormat = Cache.getProperty("DEFAULT_FILE_FORMAT");
-        JalviewFileChooser.forRead(Cache.getProperty("LAST_DIRECTORY"),
-                fileFormat);
-        Cache.log.debug("Filechooser init thread finished.");
-      }
-    }).start();
-    // Add the service change listener
-    changeSupport.addJalviewPropertyChangeListener("services",
-            new PropertyChangeListener()
-            {
-
-              @Override
-              public void propertyChange(PropertyChangeEvent evt)
-              {
-                Cache.log.debug("Firing service changed event for "
-                        + evt.getNewValue());
-                JalviewServicesChanged(evt);
-              }
-
-            });
+      t.printStackTrace();
+    }
   }
 
   /**
@@ -512,33 +623,32 @@ public class Desktop extends jalview.jbgui.GDesktop
   {
     final Desktop me = this;
     // Thread off the news reader, in case there are connection problems.
-    addDialogThread(new Runnable()
+    new Thread(new Runnable()
     {
       @Override
       public void run()
       {
         Cache.log.debug("Starting news thread.");
-
         jvnews = new BlogReader(me);
         showNews.setVisible(true);
         Cache.log.debug("Completed news thread.");
       }
-    });
+    }).start();
   }
 
   public void getIdentifiersOrgData()
   {
     // Thread off the identifiers fetcher
-    addDialogThread(new Runnable()
+    new Thread(new Runnable()
     {
       @Override
       public void run()
       {
         Cache.log.debug("Downloading data from identifiers.org");
-        UrlDownloadClient client = new UrlDownloadClient();
+        // UrlDownloadClient client = new UrlDownloadClient();
         try
         {
-          client.download(IdOrgSettings.getUrl(),
+          UrlDownloadClient.download(IdOrgSettings.getUrl(),
                   IdOrgSettings.getDownloadLocation());
         } catch (IOException e)
         {
@@ -546,7 +656,8 @@ public class Desktop extends jalview.jbgui.GDesktop
                   + e.getMessage());
         }
       }
-    });
+    }).start();
+    
   }
 
   @Override
@@ -555,28 +666,25 @@ public class Desktop extends jalview.jbgui.GDesktop
     showNews(showNews.isSelected());
   }
 
-  void showNews(boolean visible)
+  protected void showNews(boolean visible)
   {
+    Cache.log.debug((visible ? "Showing" : "Hiding") + " news.");
+    showNews.setSelected(visible);
+    if (visible && !jvnews.isVisible())
     {
-      Cache.log.debug((visible ? "Showing" : "Hiding") + " news.");
-      showNews.setSelected(visible);
-      if (visible && !jvnews.isVisible())
+      new Thread(new Runnable()
       {
-        new Thread(new Runnable()
+        @Override
+        public void run()
         {
-          @Override
-          public void run()
-          {
-            long now = System.currentTimeMillis();
-            Desktop.instance.setProgressBar(
-                    MessageManager.getString("status.refreshing_news"),
-                    now);
-            jvnews.refreshNews();
-            Desktop.instance.setProgressBar(null, now);
-            jvnews.showNews();
-          }
-        }).start();
-      }
+          long now = System.currentTimeMillis();
+          setProgressBar(
+                  MessageManager.getString("status.refreshing_news"), now);
+          jvnews.refreshNews();
+          setProgressBar(null, now);
+          jvnews.showNews();
+        }
+      }).start();
     }
   }
 
@@ -640,7 +748,7 @@ public class Desktop extends jalview.jbgui.GDesktop
 
   private void doVamsasClientCheck()
   {
-    if (jalview.bin.Cache.vamsasJarsPresent())
+    if (Cache.vamsasJarsPresent())
     {
       setupVamsasDisconnectedGui();
       VamsasMenu.setVisible(true);
@@ -678,7 +786,7 @@ public class Desktop extends jalview.jbgui.GDesktop
     }
   }
 
-  void showPasteMenu(int x, int y)
+  protected void showPasteMenu(int x, int y)
   {
     JPopupMenu popup = new JPopupMenu();
     JMenuItem item = new JMenuItem(
@@ -711,7 +819,7 @@ public class Desktop extends jalview.jbgui.GDesktop
         FileFormatI format = new IdentifyFile().identify(file,
                 DataSourceType.PASTE);
 
-        new FileLoader().LoadFile(file, DataSourceType.PASTE, format);
+        new FileLoader().loadFile(file, DataSourceType.PASTE, format);
 
       }
     } catch (Exception ex)
@@ -806,22 +914,22 @@ public class Desktop extends jalview.jbgui.GDesktop
           int w, int h, boolean resizable, boolean ignoreMinSize)
   {
 
+
     // TODO: allow callers to determine X and Y position of frame (eg. via
     // bounds object).
     // TODO: consider fixing method to update entries in the window submenu with
     // the current window title
 
     frame.setTitle(title);
-    if (frame.getWidth() < 1 || frame.getHeight() < 1)
+    if (w > 0 && (frame.getWidth() < 1 || frame.getHeight() < 1))
     {
       frame.setSize(w, h);
     }
     // THIS IS A PUBLIC STATIC METHOD, SO IT MAY BE CALLED EVEN IN
     // A HEADLESS STATE WHEN NO DESKTOP EXISTS. MUST RETURN
-    // IF JALVIEW IS RUNNING HEADLESS
+    // IF JALVIEW IS RUNNING HEADLESS OR IN INSTANCE-ONLY (testNG) MODE
     // ///////////////////////////////////////////////
-    if (instance == null || (System.getProperty("java.awt.headless") != null
-            && System.getProperty("java.awt.headless").equals("true")))
+    if (Jalview.isHeadlessMode() || Desktop.getInstance().instanceOnly)
     {
       return;
     }
@@ -849,9 +957,10 @@ public class Desktop extends jalview.jbgui.GDesktop
     frame.setResizable(resizable);
     frame.setMaximizable(resizable);
     frame.setIconifiable(resizable);
-    frame.setOpaque(false);
+    frame.setOpaque(Platform.isJS());
 
-    if (frame.getX() < 1 && frame.getY() < 1)
+    boolean isEmbedded = (Platform.getDimIfEmbedded(frame, -1, -1) != null);
+    if (!isEmbedded && frame.getX() < 1 && frame.getY() < 1)
     {
       frame.setLocation(xOffset * openFrameCount,
               yOffset * ((openFrameCount - 1) % 10) + yOffset);
@@ -861,13 +970,13 @@ public class Desktop extends jalview.jbgui.GDesktop
      * add an entry for the new frame in the Window menu 
      * (and remove it when the frame is closed)
      */
-    final JMenuItem menuItem = new JMenuItem(title);
+    JMenuItem menuItem = new JMenuItem(title);
     frame.addInternalFrameListener(new InternalFrameAdapter()
     {
       @Override
       public void internalFrameActivated(InternalFrameEvent evt)
       {
-        JInternalFrame itf = desktop.getSelectedFrame();
+        JInternalFrame itf = getDesktopPane().getSelectedFrame();
         if (itf != null)
         {
           if (itf instanceof AlignFrame)
@@ -899,10 +1008,8 @@ public class Desktop extends jalview.jbgui.GDesktop
         {
           menuItem.removeActionListener(menuItem.getActionListeners()[0]);
         }
-        windowMenu.remove(menuItem);
-
-        System.gc();
-      };
+        Desktop.getInstance().windowMenu.remove(menuItem);
+      }
     });
 
     menuItem.addActionListener(new ActionListener()
@@ -916,14 +1023,16 @@ public class Desktop extends jalview.jbgui.GDesktop
           frame.setIcon(false);
         } catch (java.beans.PropertyVetoException ex)
         {
-
+          // System.err.println(ex.toString());
         }
       }
     });
 
-    desktop.add(frame);
+    setKeyBindings(frame);
+
+    getDesktopPane().add(frame);
 
-    windowMenu.add(menuItem);
+    Desktop.getInstance().windowMenu.add(menuItem);
 
     frame.toFront();
     try
@@ -940,12 +1049,47 @@ public class Desktop extends jalview.jbgui.GDesktop
     }
   }
 
+  /**
+   * Add key bindings to a JInternalFrame so that Ctrl-W and Cmd-W will close the
+   * window
+   * 
+   * @param frame
+   */
+  private static void setKeyBindings(JInternalFrame frame)
+  {
+    final Action closeAction = new AbstractAction()
+    {
+      @Override
+      public void actionPerformed(ActionEvent e)
+      {
+        frame.dispose();
+      }
+    };
+
+    /*
+     * set up key bindings for Ctrl-W and Cmd-W, with the same (Close) action
+     */
+    KeyStroke ctrlWKey = KeyStroke.getKeyStroke(KeyEvent.VK_W,
+            InputEvent.CTRL_DOWN_MASK);
+    KeyStroke cmdWKey = KeyStroke.getKeyStroke(KeyEvent.VK_W,
+            Toolkit.getDefaultToolkit().getMenuShortcutKeyMask());
+
+    InputMap inputMap = frame
+            .getInputMap(JComponent.WHEN_IN_FOCUSED_WINDOW);
+    String ctrlW = ctrlWKey.toString();
+    inputMap.put(ctrlWKey, ctrlW);
+    inputMap.put(cmdWKey, ctrlW);
+
+    ActionMap actionMap = frame.getActionMap();
+    actionMap.put(ctrlW, closeAction);
+  }
+
   @Override
   public void lostOwnership(Clipboard clipboard, Transferable contents)
   {
     if (!internalCopy)
     {
-      Desktop.jalviewClipboard = null;
+      Desktop.getInstance().jalviewClipboard = null;
     }
 
     internalCopy = false;
@@ -985,7 +1129,7 @@ public class Desktop extends jalview.jbgui.GDesktop
     // Java's Transferable for native dnd
     evt.acceptDrop(DnDConstants.ACTION_COPY_OR_MOVE);
     Transferable t = evt.getTransferable();
-    List<String> files = new ArrayList<>();
+    List<Object> files = new ArrayList<>();
     List<DataSourceType> protocols = new ArrayList<>();
 
     try
@@ -1003,13 +1147,15 @@ public class Desktop extends jalview.jbgui.GDesktop
       {
         for (int i = 0; i < files.size(); i++)
         {
-          String file = files.get(i).toString();
+          // BH 2018 File or String
+          Object file = files.get(i);
+          String fileName = file.toString();
           DataSourceType protocol = (protocols == null)
                   ? DataSourceType.FILE
                   : protocols.get(i);
           FileFormatI format = null;
 
-          if (file.endsWith(".jar"))
+          if (fileName.endsWith(".jar"))
           {
             format = FileFormat.Jalview;
 
@@ -1018,8 +1164,11 @@ public class Desktop extends jalview.jbgui.GDesktop
           {
             format = new IdentifyFile().identify(file, protocol);
           }
-
-          new FileLoader().LoadFile(file, protocol, format);
+          if (file instanceof File)
+          {
+            Platform.cacheFileData((File) file);
+          }
+          new FileLoader().loadFile(null, file, protocol, format);
 
         }
       } catch (Exception ex)
@@ -1042,56 +1191,51 @@ public class Desktop extends jalview.jbgui.GDesktop
   {
     String fileFormat = Cache.getProperty("DEFAULT_FILE_FORMAT");
     JalviewFileChooser chooser = JalviewFileChooser
-            .forRead(Cache.getProperty("LAST_DIRECTORY"), fileFormat);
+            .forRead(Cache.getProperty("LAST_DIRECTORY"), fileFormat, true);
 
     chooser.setFileView(new JalviewFileView());
     chooser.setDialogTitle(
             MessageManager.getString("label.open_local_file"));
     chooser.setToolTipText(MessageManager.getString("action.open"));
 
-    int value = chooser.showOpenDialog(this);
-
-    if (value == JalviewFileChooser.APPROVE_OPTION)
+    chooser.setResponseHandler(0, new Runnable()
     {
-      String choice = chooser.getSelectedFile().getPath();
-      Cache.setProperty("LAST_DIRECTORY",
-              chooser.getSelectedFile().getParent());
+      @Override
+      public void run()
+      {
+        File selectedFile = chooser.getSelectedFile();
+        Cache.setProperty("LAST_DIRECTORY", selectedFile.getParent());
 
-      FileFormatI format = chooser.getSelectedFormat();
+        FileFormatI format = chooser.getSelectedFormat();
 
-      /*
-       * Call IdentifyFile to verify the file contains what its extension implies.
-       * Skip this step for dynamically added file formats, because
-       * IdentifyFile does not know how to recognise them.
-       */
-      if (FileFormats.getInstance().isIdentifiable(format))
-      {
-        try
-        {
-          format = new IdentifyFile().identify(choice, DataSourceType.FILE);
-        } catch (FileFormatException e)
+        /*
+         * Call IdentifyFile to verify the file contains what its extension implies.
+         * Skip this step for dynamically added file formats, because
+         * IdentifyFile does not know how to recognise them.
+         */
+        if (FileFormats.getInstance().isIdentifiable(format))
         {
-          // format = null; //??
+          try
+          {
+            format = new IdentifyFile().identify(selectedFile,
+                    DataSourceType.FILE);
+          } catch (FileFormatException e)
+          {
+            // format = null; //??
+          }
         }
-      }
 
-      if (viewport != null)
-      {
-        new FileLoader().LoadFile(viewport, choice, DataSourceType.FILE,
-                format);
-      }
-      else
-      {
-        new FileLoader().LoadFile(choice, DataSourceType.FILE, format);
+        new FileLoader().loadFile(viewport, selectedFile,
+                DataSourceType.FILE, format);
       }
-    }
+    });
+    chooser.showOpenDialog(this);
   }
 
   /**
-   * DOCUMENT ME!
+   * Shows a dialog for input of a URL at which to retrieve alignment data
    * 
-   * @param e
-   *          DOCUMENT ME!
+   * @param viewport
    */
   @Override
   public void inputURLMenuItem_actionPerformed(AlignViewport viewport)
@@ -1100,87 +1244,114 @@ public class Desktop extends jalview.jbgui.GDesktop
     // for viewing
     JLabel label = new JLabel(
             MessageManager.getString("label.input_file_url"));
-    final JComboBox history = new JComboBox();
 
     JPanel panel = new JPanel(new GridLayout(2, 1));
     panel.add(label);
-    panel.add(history);
-    history.setPreferredSize(new Dimension(400, 20));
-    history.setEditable(true);
-    history.addItem("http://www.");
 
-    String historyItems = jalview.bin.Cache.getProperty("RECENT_URL");
-
-    StringTokenizer st;
-
-    if (historyItems != null)
-    {
-      st = new StringTokenizer(historyItems, "\t");
-
-      while (st.hasMoreTokens())
-      {
-        history.addItem(st.nextElement());
-      }
-    }
-
-    int reply = JvOptionPane.showInternalConfirmDialog(desktop, panel,
-            MessageManager.getString("label.input_alignment_from_url"),
-            JvOptionPane.OK_CANCEL_OPTION);
-
-    if (reply != JvOptionPane.OK_OPTION)
+    /*
+     * the URL to fetch is
+     * Java: an editable combobox with history
+     * JS: (pending JAL-3038) a plain text field
+     */
+    JComponent history;
+    String urlBase = "http://www.";
+    if (Platform.isJS())
     {
-      return;
+      history = new JTextField(urlBase, 35);
     }
-
-    String url = history.getSelectedItem().toString();
-
-    if (url.toLowerCase().endsWith(".jar"))
+    else
+    /**
+     * Java only
+     * 
+     * @j2sIgnore
+     */
     {
-      if (viewport != null)
+      JComboBox<String> asCombo = new JComboBox<>();
+      asCombo.setPreferredSize(new Dimension(400, 20));
+      asCombo.setEditable(true);
+      asCombo.addItem(urlBase);
+      String historyItems = Cache.getProperty("RECENT_URL");
+      if (historyItems != null)
       {
-        new FileLoader().LoadFile(viewport, url, DataSourceType.URL,
-                FileFormat.Jalview);
-      }
-      else
-      {
-        new FileLoader().LoadFile(url, DataSourceType.URL,
-                FileFormat.Jalview);
+        for (String token : historyItems.split("\\t"))
+        {
+          asCombo.addItem(token);
+        }
       }
+      history = asCombo;
     }
-    else
+    panel.add(history);
+
+    Object[] options = new Object[] { MessageManager.getString("action.ok"),
+        MessageManager.getString("action.cancel") };
+    Runnable action = new Runnable()
     {
-      FileFormatI format = null;
-      try
-      {
-        format = new IdentifyFile().identify(url, DataSourceType.URL);
-      } catch (FileFormatException e)
+      @Override
+      public void run()
       {
-        // TODO revise error handling, distinguish between
-        // URL not found and response not valid
-      }
+        @SuppressWarnings("unchecked")
+        String url = (history instanceof JTextField
+                ? ((JTextField) history).getText()
+                : ((JComboBox<String>) history).getSelectedItem()
+                        .toString());
 
-      if (format == null)
-      {
-        JvOptionPane.showInternalMessageDialog(Desktop.desktop,
-                MessageManager.formatMessage("label.couldnt_locate",
-                        new Object[]
-                        { url }),
-                MessageManager.getString("label.url_not_found"),
-                JvOptionPane.WARNING_MESSAGE);
+        if (url.toLowerCase().endsWith(".jar"))
+        {
+          if (viewport != null)
+          {
+            new FileLoader().loadFile(viewport, url, DataSourceType.URL,
+                    FileFormat.Jalview);
+          }
+          else
+          {
+            new FileLoader().loadFile(url, DataSourceType.URL,
+                    FileFormat.Jalview);
+          }
+        }
+        else
+        {
+          FileFormatI format = null;
+          try
+          {
+            format = new IdentifyFile().identify(url, DataSourceType.URL);
+          } catch (FileFormatException e)
+          {
+            // TODO revise error handling, distinguish between
+            // URL not found and response not valid
+          }
 
-        return;
-      }
+          if (format == null)
+          {
+            String msg = MessageManager
+                    .formatMessage("label.couldnt_locate", url);
+            JvOptionPane.showInternalMessageDialog(Desktop.getDesktopPane(),
+                    msg,
+                    MessageManager.getString("label.url_not_found"),
+                    JvOptionPane.WARNING_MESSAGE);
 
-      if (viewport != null)
-      {
-        new FileLoader().LoadFile(viewport, url, DataSourceType.URL,
-                format);
-      }
-      else
-      {
-        new FileLoader().LoadFile(url, DataSourceType.URL, format);
+            return;
+          }
+
+          if (viewport != null)
+          {
+            new FileLoader().loadFile(viewport, url, DataSourceType.URL,
+                    format);
+          }
+          else
+          {
+            new FileLoader().loadFile(url, DataSourceType.URL, format);
+          }
+        }
       }
-    }
+    };
+    String dialogOption = MessageManager
+            .getString("label.input_alignment_from_url");
+    JvOptionPane.newOptionDialog(getDesktopPane())
+            .setResponseHandler(0, action)
+            .showInternalDialog(panel, dialogOption,
+                    JvOptionPane.YES_NO_CANCEL_OPTION,
+                    JvOptionPane.PLAIN_MESSAGE, null, options,
+                    MessageManager.getString("action.ok"));
   }
 
   /**
@@ -1262,7 +1433,7 @@ public class Desktop extends jalview.jbgui.GDesktop
   public void aboutMenuItem_actionPerformed(ActionEvent e)
   {
     // StringBuffer message = getAboutMessage(false);
-    // JvOptionPane.showInternalMessageDialog(Desktop.desktop,
+    // JvOptionPane.showInternalMessageDialog(Desktop.getDesktop(),
     //
     // message.toString(), "About Jalview", JvOptionPane.INFORMATION_MESSAGE);
     new Thread(new Runnable()
@@ -1342,27 +1513,41 @@ public class Desktop extends jalview.jbgui.GDesktop
   }
 
   /**
-   * DOCUMENT ME!
-   * 
-   * @param e
-   *          DOCUMENT ME!
+   * Action on requesting Help documentation
    */
   @Override
-  public void documentationMenuItem_actionPerformed(ActionEvent e)
+  public void documentationMenuItem_actionPerformed()
   {
     try
     {
-      Help.showHelpWindow();
+      if (Platform.isJS())
+      {
+        BrowserLauncher.openURL("http://www.jalview.org/help.html");
+      }
+      else
+      /**
+       * Java only
+       * 
+       * @j2sIgnore
+       */
+      {
+        Help.showHelpWindow();
+      }
     } catch (Exception ex)
     {
+      System.err.println("Error opening help: " + ex.getMessage());
     }
   }
 
   @Override
   public void closeAll_actionPerformed(ActionEvent e)
   {
+    if (desktopPane == null)
+    {
+      return;
+    }
     // TODO show a progress bar while closing?
-    JInternalFrame[] frames = desktop.getAllFrames();
+    JInternalFrame[] frames = desktopPane.getAllFrames();
     for (int i = 0; i < frames.length; i++)
     {
       try
@@ -1383,13 +1568,7 @@ public class Desktop extends jalview.jbgui.GDesktop
      * reset state of singleton objects as appropriate (clear down session state
      * when all windows are closed)
      */
-    StructureSelectionManager ssm = StructureSelectionManager
-            .getStructureSelectionManager(this);
-    if (ssm != null)
-    {
-      ssm.resetAll();
-    }
-    System.gc();
+    getStructureSelectionManager().resetAll();
   }
 
   @Override
@@ -1434,7 +1613,7 @@ public class Desktop extends jalview.jbgui.GDesktop
   @Override
   protected void showMemusage_actionPerformed(ActionEvent e)
   {
-    desktop.showMemoryUsage(showMemusage.isSelected());
+    getDesktopPane().showMemoryUsage(showMemusage.isSelected());
   }
 
   /*
@@ -1459,16 +1638,19 @@ public class Desktop extends jalview.jbgui.GDesktop
    */
   void showConsole(boolean selected)
   {
-    showConsole.setSelected(selected);
     // TODO: decide if we should update properties file
-    Cache.setProperty("SHOW_JAVA_CONSOLE",
-            Boolean.valueOf(selected).toString());
-    jconsole.setVisible(selected);
+    if (jconsole != null) // BH 2018
+    {
+      showConsole.setSelected(selected);
+      Cache.setProperty("SHOW_JAVA_CONSOLE",
+              Boolean.valueOf(selected).toString());
+      jconsole.setVisible(selected);
+    }
   }
 
   void reorderAssociatedWindows(boolean minimize, boolean close)
   {
-    JInternalFrame[] frames = desktop.getAllFrames();
+    JInternalFrame[] frames = getDesktopPane().getAllFrames();
     if (frames == null || frames.length < 1)
     {
       return;
@@ -1556,28 +1738,49 @@ public class Desktop extends jalview.jbgui.GDesktop
   }
 
   /**
-   * DOCUMENT ME!
-   * 
-   * @param e
-   *          DOCUMENT ME!
+   * Prompts the user to choose a file and then saves the Jalview state as a
+   * Jalview project file
    */
   @Override
-  public void saveState_actionPerformed(ActionEvent e)
+  public void saveState_actionPerformed()
   {
-    JalviewFileChooser chooser = new JalviewFileChooser("jvp",
-            "Jalview Project");
+    saveState_actionPerformed(false);
+  }
 
-    chooser.setFileView(new JalviewFileView());
-    chooser.setDialogTitle(MessageManager.getString("label.save_state"));
+  public void saveState_actionPerformed(boolean saveAs)
+  {
+    java.io.File projectFile = getProjectFile();
+    // autoSave indicates we already have a file and don't need to ask
+    boolean autoSave = projectFile != null && !saveAs
+            && BackupFiles.getEnabled();
 
-    int value = chooser.showSaveDialog(this);
+    // System.out.println("autoSave="+autoSave+", projectFile='"+projectFile+"',
+    // saveAs="+saveAs+", Backups
+    // "+(BackupFiles.getEnabled()?"enabled":"disabled"));
 
-    if (value == JalviewFileChooser.APPROVE_OPTION)
+    boolean approveSave = false;
+    if (!autoSave)
     {
-      final Desktop me = this;
-      final java.io.File choice = chooser.getSelectedFile();
-      setProjectFile(choice);
+      JalviewFileChooser chooser = new JalviewFileChooser("jvp",
+              "Jalview Project");
+
+      chooser.setFileView(new JalviewFileView());
+      chooser.setDialogTitle(MessageManager.getString("label.save_state"));
+
+      int value = chooser.showSaveDialog(this);
+
+      if (value == JalviewFileChooser.APPROVE_OPTION)
+      {
+        projectFile = chooser.getSelectedFile();
+        setProjectFile(projectFile);
+        approveSave = true;
+      }
+    }
 
+    if (approveSave || autoSave)
+    {
+      final Desktop me = this;
+      final java.io.File chosenFile = projectFile;
       new Thread(new Runnable()
       {
         @Override
@@ -1586,39 +1789,52 @@ public class Desktop extends jalview.jbgui.GDesktop
           // TODO: refactor to Jalview desktop session controller action.
           setProgressBar(MessageManager.formatMessage(
                   "label.saving_jalview_project", new Object[]
-                  { choice.getName() }), choice.hashCode());
+                  { chosenFile.getName() }), chosenFile.hashCode());
           jalview.bin.Cache.setProperty("LAST_DIRECTORY",
-                  choice.getParent());
+                  chosenFile.getParent());
           // TODO catch and handle errors for savestate
           // TODO prevent user from messing with the Desktop whilst we're saving
           try
           {
-            new Jalview2XML().saveState(choice);
+               boolean doBackup = BackupFiles.getEnabled();
+            BackupFiles backupfiles = doBackup ? new BackupFiles(chosenFile) : null;
+
+            new Jalview2XML().saveState(doBackup ? backupfiles.getTempFile() : chosenFile);
+
+            if (doBackup)
+            {
+              backupfiles.setWriteSuccess(true);
+              backupfiles.rollBackupsAndRenameTempFile();
+            }
           } catch (OutOfMemoryError oom)
           {
-            new OOMWarning(
-                    "Whilst saving current state to " + choice.getName(),
-                    oom);
+            new OOMWarning("Whilst saving current state to "
+                    + chosenFile.getName(), oom);
           } catch (Exception ex)
           {
-            Cache.log.error(
-                    "Problems whilst trying to save to " + choice.getName(),
-                    ex);
+            Cache.log.error("Problems whilst trying to save to "
+                    + chosenFile.getName(), ex);
             JvOptionPane.showMessageDialog(me,
                     MessageManager.formatMessage(
                             "label.error_whilst_saving_current_state_to",
                             new Object[]
-                            { choice.getName() }),
+                            { chosenFile.getName() }),
                     MessageManager.getString("label.couldnt_save_project"),
                     JvOptionPane.WARNING_MESSAGE);
           }
-          setProgressBar(null, choice.hashCode());
+          setProgressBar(null, chosenFile.hashCode());
         }
       }).start();
-    }
+      }
+  }
+
+  @Override
+  public void saveAsState_actionPerformed(ActionEvent e)
+  {
+    saveState_actionPerformed(true);
   }
 
-  private void setProjectFile(File choice)
+  protected void setProjectFile(File choice)
   {
     this.projectFile = choice;
   }
@@ -1629,61 +1845,59 @@ public class Desktop extends jalview.jbgui.GDesktop
   }
 
   /**
-   * DOCUMENT ME!
-   * 
-   * @param e
-   *          DOCUMENT ME!
+   * Shows a file chooser dialog and tries to read in the selected file as a
+   * Jalview project
    */
   @Override
-  public void loadState_actionPerformed(ActionEvent e)
+  public void loadState_actionPerformed()
   {
+    final String[] suffix = new String[] { "jvp", "jar" };
+    final String[] desc = new String[] { "Jalview Project",
+        "Jalview Project (old)" };
     JalviewFileChooser chooser = new JalviewFileChooser(
-            Cache.getProperty("LAST_DIRECTORY"), new String[]
-            { "jvp", "jar" },
-            new String[]
-            { "Jalview Project", "Jalview Project (old)" },
-            "Jalview Project");
+            Cache.getProperty("LAST_DIRECTORY"), suffix, desc,
+            "Jalview Project", true, true); // last two booleans: allFiles,
+                                            // allowBackupFiles
     chooser.setFileView(new JalviewFileView());
     chooser.setDialogTitle(MessageManager.getString("label.restore_state"));
-
-    int value = chooser.showOpenDialog(this);
-
-    if (value == JalviewFileChooser.APPROVE_OPTION)
+    chooser.setResponseHandler(0, new Runnable()
     {
-      final File selectedFile = chooser.getSelectedFile();
-      setProjectFile(selectedFile);
-      final String choice = selectedFile.getAbsolutePath();
-      Cache.setProperty("LAST_DIRECTORY", selectedFile.getParent());
-      new Thread(new Runnable()
+      @Override
+      public void run()
       {
-        @Override
-        public void run()
+        File selectedFile = chooser.getSelectedFile();
+        setProjectFile(selectedFile);
+        String choice = selectedFile.getAbsolutePath();
+        Cache.setProperty("LAST_DIRECTORY", selectedFile.getParent());
+        new Thread(new Runnable()
         {
-          setProgressBar(MessageManager.formatMessage(
-                  "label.loading_jalview_project", new Object[]
-                  { choice }), choice.hashCode());
-          try
-          {
-            new Jalview2XML().loadJalviewAlign(choice);
-          } catch (OutOfMemoryError oom)
-          {
-            new OOMWarning("Whilst loading project from " + choice, oom);
-          } catch (Exception ex)
+          @Override
+          public void run()
           {
-            Cache.log.error(
-                    "Problems whilst loading project from " + choice, ex);
-            JvOptionPane.showMessageDialog(Desktop.desktop,
-                    MessageManager.formatMessage(
-                            "label.error_whilst_loading_project_from",
-                            new Object[]
-                            { choice }),
-                    MessageManager.getString("label.couldnt_load_project"),
-                    JvOptionPane.WARNING_MESSAGE);
+               try 
+            {
+              new Jalview2XML().loadJalviewAlign(choice);
+            } catch (OutOfMemoryError oom)
+               {
+                 new OOMWarning("Whilst loading project from " + choice, oom);
+               } catch (Exception ex)
+               {
+                 Cache.log.error(
+                         "Problems whilst loading project from " + choice, ex);
+              JvOptionPane.showMessageDialog(Desktop.getDesktopPane(),
+                         MessageManager.formatMessage(
+                                 "label.error_whilst_loading_project_from",
+                               new Object[]
+                                   { choice }),
+                         MessageManager.getString("label.couldnt_load_project"),
+                         JvOptionPane.WARNING_MESSAGE);
+               }
           }
-          setProgressBar(null, choice.hashCode());
-        }
-      }).start();
-    }
+        }).start();
+      }
+    });
+    
+    chooser.showOpenDialog(this);
   }
 
   @Override
@@ -1696,7 +1910,7 @@ public class Desktop extends jalview.jbgui.GDesktop
 
   ArrayList<JPanel> fileLoadingPanels = new ArrayList<>();
 
-  public void startLoading(final String fileName)
+  public void startLoading(final Object fileName)
   {
     if (fileLoadingCount == 0)
     {
@@ -1713,7 +1927,7 @@ public class Desktop extends jalview.jbgui.GDesktop
     {
       progressPanel = new JPanel(new GridLayout(1, 1));
       totalProgressCount = 0;
-      instance.getContentPane().add(progressPanel, BorderLayout.SOUTH);
+      getContentPane().add(progressPanel, BorderLayout.SOUTH);
     }
     JPanel thisprogress = new JPanel(new BorderLayout(10, 5));
     JProgressBar progressBar = new JProgressBar();
@@ -1726,7 +1940,7 @@ public class Desktop extends jalview.jbgui.GDesktop
     ((GridLayout) progressPanel.getLayout()).setRows(
             ((GridLayout) progressPanel.getLayout()).getRows() + 1);
     ++totalProgressCount;
-    instance.validate();
+    validate();
     return thisprogress;
   }
 
@@ -1780,7 +1994,7 @@ public class Desktop extends jalview.jbgui.GDesktop
    */
   public static AlignmentPanel[] getAlignmentPanels(String alignmentId)
   {
-    if (Desktop.desktop == null)
+    if (Desktop.getDesktopPane() == null)
     {
       // no frames created and in headless mode
       // TODO: verify that frames are recoverable when in headless mode
@@ -1822,7 +2036,7 @@ public class Desktop extends jalview.jbgui.GDesktop
   public static AlignmentViewport[] getViewports(String sequenceSetId)
   {
     List<AlignmentViewport> viewp = new ArrayList<>();
-    if (desktop != null)
+    if (getDesktopPane() != null)
     {
       AlignFrame[] frames = Desktop.getAlignFrames();
 
@@ -1898,9 +2112,9 @@ public class Desktop extends jalview.jbgui.GDesktop
 
   /**
    * Gather expanded views (separate AlignFrame's) with the same sequence set
-   * identifier back in to this frame as additional views, and close the
-   * expanded views. Note the expanded frames may themselves have multiple
-   * views. We take the lot.
+   * identifier back in to this frame as additional views, and close the expanded
+   * views. Note the expanded frames may themselves have multiple views. We take
+   * the lot.
    * 
    * @param source
    */
@@ -1908,7 +2122,7 @@ public class Desktop extends jalview.jbgui.GDesktop
   {
     source.viewport.setGatherViewsHere(true);
     source.viewport.setExplodedGeometry(source.getBounds());
-    JInternalFrame[] frames = desktop.getAllFrames();
+    JInternalFrame[] frames = getAllFrames();
     String viewId = source.viewport.getSequenceSetId();
 
     for (int t = 0; t < frames.length; t++)
@@ -1944,6 +2158,8 @@ public class Desktop extends jalview.jbgui.GDesktop
   @Override
   public void vamsasImport_actionPerformed(ActionEvent e)
   {
+    // TODO: JAL-3048 not needed for Jalview-JS
+
     if (v_client == null)
     {
       // Load and try to start a session.
@@ -1963,7 +2179,7 @@ public class Desktop extends jalview.jbgui.GDesktop
         String fle = chooser.getSelectedFile().toString();
         if (!vamsasImport(chooser.getSelectedFile()))
         {
-          JvOptionPane.showInternalMessageDialog(Desktop.desktop,
+          JvOptionPane.showInternalMessageDialog(Desktop.getDesktopPane(),
                   MessageManager.formatMessage(
                           "label.couldnt_import_as_vamsas_session",
                           new Object[]
@@ -2195,7 +2411,7 @@ public class Desktop extends jalview.jbgui.GDesktop
                 });
                 rthr.start();
               }
-            };
+            }
           });
           VamsasStMenu.add(sessit);
         }
@@ -2220,6 +2436,8 @@ public class Desktop extends jalview.jbgui.GDesktop
   @Override
   public void vamsasSave_actionPerformed(ActionEvent e)
   {
+    // TODO: JAL-3048 not needed for Jalview-JS
+
     if (v_client != null)
     {
       // TODO: VAMSAS DOCUMENT EXTENSION is VDJ
@@ -2262,7 +2480,7 @@ public class Desktop extends jalview.jbgui.GDesktop
         removeProgressPanel(progpanel);
         if (warnmsg != null)
         {
-          JvOptionPane.showInternalMessageDialog(Desktop.desktop,
+          JvOptionPane.showInternalMessageDialog(Desktop.getDesktopPane(),
 
                   warnmsg, warnttl, JvOptionPane.ERROR_MESSAGE);
         }
@@ -2299,7 +2517,7 @@ public class Desktop extends jalview.jbgui.GDesktop
 
   public JInternalFrame[] getAllFrames()
   {
-    return desktop.getAllFrames();
+    return desktopPane.getAllFrames();
   }
 
   /**
@@ -2338,7 +2556,7 @@ public class Desktop extends jalview.jbgui.GDesktop
           while (li.hasNext())
           {
             String link = li.next();
-            if (link.contains(SEQUENCE_ID)
+            if (link.contains(UrlConstants.SEQUENCE_ID)
                     && !UrlConstants.isDefaultString(link))
             {
               check = true;
@@ -2385,7 +2603,7 @@ public class Desktop extends jalview.jbgui.GDesktop
           });
           msgPanel.add(jcb);
 
-          JvOptionPane.showMessageDialog(Desktop.desktop, msgPanel,
+          JvOptionPane.showMessageDialog(desktopPane, msgPanel,
                   MessageManager
                           .getString("label.SEQUENCE_ID_no_longer_used"),
                   JvOptionPane.WARNING_MESSAGE);
@@ -2396,14 +2614,13 @@ public class Desktop extends jalview.jbgui.GDesktop
 
   /**
    * Proxy class for JDesktopPane which optionally displays the current memory
-   * usage and highlights the desktop area with a red bar if free memory runs
-   * low.
+   * usage and highlights the desktop area with a red bar if free memory runs low.
    * 
    * @author AMW
    */
-  public class MyDesktopPane extends JDesktopPane implements Runnable
+  public class MyDesktopPane extends JDesktopPane
+          implements Runnable
   {
-
     private static final float ONE_MB = 1048576f;
 
     boolean showMemoryUsage = false;
@@ -2492,7 +2709,6 @@ public class Desktop extends jalview.jbgui.GDesktop
     }
   }
 
-
   /**
    * Accessor method to quickly get all the AlignmentFrames loaded.
    * 
@@ -2502,11 +2718,11 @@ public class Desktop extends jalview.jbgui.GDesktop
   {
     if (Jalview.isHeadlessMode())
     {
-      // Desktop.desktop is null in headless mode
-      return new AlignFrame[] { Jalview.currentAlignFrame };
+      // Desktop.getDesktop() is null in headless mode
+      return new AlignFrame[] { Jalview.getCurrentAlignFrame() };
     }
 
-    JInternalFrame[] frames = Desktop.desktop.getAllFrames();
+    JInternalFrame[] frames = Desktop.getDesktopPane().getAllFrames();
 
     if (frames == null)
     {
@@ -2551,7 +2767,7 @@ public class Desktop extends jalview.jbgui.GDesktop
    */
   public GStructureViewer[] getJmols()
   {
-    JInternalFrame[] frames = Desktop.desktop.getAllFrames();
+    JInternalFrame[] frames = Desktop.getDesktopPane().getAllFrames();
 
     if (frames == null)
     {
@@ -2587,7 +2803,7 @@ public class Desktop extends jalview.jbgui.GDesktop
     } catch (Exception ex)
     {
       jalview.bin.Cache.log.error("Groovy Shell Creation failed.", ex);
-      JvOptionPane.showInternalMessageDialog(Desktop.desktop,
+      JvOptionPane.showInternalMessageDialog(desktopPane,
 
               MessageManager.getString("label.couldnt_create_groovy_shell"),
               MessageManager.getString("label.groovy_support_failed"),
@@ -2598,7 +2814,7 @@ public class Desktop extends jalview.jbgui.GDesktop
   /**
    * Open the Groovy console
    */
-  void openGroovyConsole()
+  private void openGroovyConsole()
   {
     if (groovyConsole == null)
     {
@@ -2640,8 +2856,8 @@ public class Desktop extends jalview.jbgui.GDesktop
   }
 
   /**
-   * Bind Ctrl/Cmd-Q to Quit - for reset as Groovy Console takes over this
-   * binding when opened
+   * Bind Ctrl/Cmd-Q to Quit - for reset as Groovy Console takes over this binding
+   * when opened
    */
   protected void addQuitHandler()
   {
@@ -2698,6 +2914,8 @@ public class Desktop extends jalview.jbgui.GDesktop
   @Override
   public void setProgressBar(String message, long id)
   {
+           Platform.timeCheck("Desktop " + message, Platform.TIME_MARK);     
+
     if (progressBars == null)
     {
       progressBars = new Hashtable<>();
@@ -2774,16 +2992,15 @@ public class Desktop extends jalview.jbgui.GDesktop
   }
 
   /**
-   * This will return the first AlignFrame holding the given viewport instance.
-   * It will break if there are more than one AlignFrames viewing a particular
-   * av.
+   * This will return the first AlignFrame holding the given viewport instance. It
+   * will break if there are more than one AlignFrames viewing a particular av.
    * 
    * @param viewport
    * @return alignFrame for viewport
    */
   public static AlignFrame getAlignFrameFor(AlignViewportI viewport)
   {
-    if (desktop != null)
+    if (getDesktopPane() != null)
     {
       AlignmentPanel[] aps = getAlignmentPanels(
               viewport.getSequenceSetId());
@@ -2844,8 +3061,8 @@ public class Desktop extends jalview.jbgui.GDesktop
       // todo: changesupport handlers need to be transferred
       if (discoverer == null)
       {
-        discoverer = new jalview.ws.jws1.Discoverer();
-        // register PCS handler for desktop.
+        discoverer = Discoverer.getInstance();
+        // register PCS handler for getDesktop().
         discoverer.addPropertyChangeListener(changeSupport);
       }
       // JAL-940 - disabled JWS1 service configuration - always start discoverer
@@ -2855,7 +3072,7 @@ public class Desktop extends jalview.jbgui.GDesktop
 
     if (Cache.getDefault("SHOW_JWS2_SERVICES", true))
     {
-      t2 = jalview.ws.jws2.Jws2Discoverer.getDiscoverer()
+      t2 = jalview.ws.jws2.Jws2Discoverer.getInstance()
               .startDiscoverer(changeSupport);
     }
     Thread t3 = null;
@@ -2888,7 +3105,7 @@ public class Desktop extends jalview.jbgui.GDesktop
   {
     if (evt.getNewValue() == null || evt.getNewValue() instanceof Vector)
     {
-      final String ermsg = jalview.ws.jws2.Jws2Discoverer.getDiscoverer()
+      final String ermsg = jalview.ws.jws2.Jws2Discoverer.getInstance()
               .getErrorMessages();
       if (ermsg != null)
       {
@@ -2927,7 +3144,7 @@ public class Desktop extends jalview.jbgui.GDesktop
                  * 
                  * jd.waitForInput();
                  */
-                JvOptionPane.showConfirmDialog(Desktop.desktop,
+                JvOptionPane.showConfirmDialog(Desktop.getDesktopPane(),
                         new JLabel("<html><table width=\"450\"><tr><td>"
                                 + ermsg + "</td></tr></table>"
                                 + "<p>It may be that you have invalid JABA URLs<br/>in your web service preferences,"
@@ -2953,7 +3170,7 @@ public class Desktop extends jalview.jbgui.GDesktop
     }
   }
 
-  private Runnable serviceChangedDialog = null;
+  Runnable serviceChangedDialog = null;
 
   /**
    * start a thread to open a URL in the configured browser. Pops up a warning
@@ -2964,7 +3181,7 @@ public class Desktop extends jalview.jbgui.GDesktop
    */
   public static void showUrl(final String url)
   {
-    showUrl(url, Desktop.instance);
+    showUrl(url, Desktop.getInstance());
   }
 
   /**
@@ -2990,10 +3207,10 @@ public class Desktop extends jalview.jbgui.GDesktop
                     .formatMessage("status.opening_params", new Object[]
                     { url }), this.hashCode());
           }
-          jalview.util.BrowserLauncher.openURL(url);
+          BrowserLauncher.openURL(url);
         } catch (Exception ex)
         {
-          JvOptionPane.showInternalMessageDialog(Desktop.desktop,
+          JvOptionPane.showInternalMessageDialog(Desktop.getDesktopPane(),
                   MessageManager
                           .getString("label.web_browser_not_found_unix"),
                   MessageManager.getString("label.web_browser_not_found"),
@@ -3009,15 +3226,16 @@ public class Desktop extends jalview.jbgui.GDesktop
     }).start();
   }
 
-  public static WsParamSetManager wsparamManager = null;
+  private WsParamSetManager wsparamManager = null;
 
   public static ParamManager getUserParameterStore()
   {
-    if (wsparamManager == null)
+    Desktop d = Desktop.getInstance();
+    if (d.wsparamManager == null)
     {
-      wsparamManager = new WsParamSetManager();
+      d.wsparamManager = new WsParamSetManager();
     }
-    return wsparamManager;
+    return d.wsparamManager;
   }
 
   /**
@@ -3062,14 +3280,16 @@ public class Desktop extends jalview.jbgui.GDesktop
   /**
    * flag indicating if dialogExecutor should try to acquire a permit
    */
-  private volatile boolean dialogPause = true;
+  volatile boolean dialogPause = true;
 
   /**
    * pause the queue
    */
-  private java.util.concurrent.Semaphore block = new Semaphore(0);
+  java.util.concurrent.Semaphore block = new Semaphore(0);
+
+  private groovy.ui.Console groovyConsole;
 
-  private static groovy.ui.Console groovyConsole;
+  public StructureViewer lastTargetedView;
 
   /**
    * add another dialog thread to the queue
@@ -3091,9 +3311,8 @@ public class Desktop extends jalview.jbgui.GDesktop
           } catch (InterruptedException x)
           {
           }
-          ;
         }
-        if (instance == null)
+        if (instanceOnly || Jalview.isHeadlessMode())
         {
           return;
         }
@@ -3116,34 +3335,45 @@ public class Desktop extends jalview.jbgui.GDesktop
     block.release();
   }
 
+  /**
+   * Outputs an image of the desktop to file in EPS format, after prompting the
+   * user for choice of Text or Lineart character rendering (unless a preference
+   * has been set). The file name is generated as
+   * 
+   * <pre>
+   * Jalview_snapshot_nnnnn.eps where nnnnn is the current timestamp in milliseconds
+   * </pre>
+   */
   @Override
   protected void snapShotWindow_actionPerformed(ActionEvent e)
   {
+    // currently the menu option to do this is not shown
     invalidate();
-    File of;
-    ImageMaker im = new jalview.util.ImageMaker(
-            this, ImageMaker.TYPE.EPS, "View of Desktop", getWidth(),
-            getHeight(), of = new File("Jalview_snapshot"
-                    + System.currentTimeMillis() + ".eps"),
-            "View of desktop", null, 0, false);
-    try
-    {
-      paintAll(im.getGraphics());
-      im.writeImage();
-    } catch (Exception q)
+
+    int width = getWidth();
+    int height = getHeight();
+    File of = new File(
+            "Jalview_snapshot_" + System.currentTimeMillis() + ".eps");
+    ImageWriterI writer = new ImageWriterI()
     {
-      Cache.log.error("Couldn't write snapshot to " + of.getAbsolutePath(),
-              q);
-      return;
-    }
-    Cache.log.info("Successfully written snapshot to file "
-            + of.getAbsolutePath());
+      @Override
+      public void exportImage(Graphics g) throws Exception
+      {
+        paintAll(g);
+        Cache.log.info("Successfully written snapshot to file "
+                + of.getAbsolutePath());
+      }
+    };
+    String title = "View of desktop";
+    ImageExporter exporter = new ImageExporter(writer, null, TYPE.EPS,
+            title);
+    exporter.doExport(of, this, width, height, title);
   }
 
   /**
    * Explode the views in the given SplitFrame into separate SplitFrame windows.
-   * This respects (remembers) any previous 'exploded geometry' i.e. the size
-   * and location last time the view was expanded (if any). However it does not
+   * This respects (remembers) any previous 'exploded geometry' i.e. the size and
+   * location last time the view was expanded (if any). However it does not
    * remember the split pane divider location - this is set to match the
    * 'exploding' frame.
    * 
@@ -3246,7 +3476,7 @@ public class Desktop extends jalview.jbgui.GDesktop
     String topViewId = myTopFrame.viewport.getSequenceSetId();
     String bottomViewId = myBottomFrame.viewport.getSequenceSetId();
 
-    JInternalFrame[] frames = desktop.getAllFrames();
+    JInternalFrame[] frames = desktopPane.getAllFrames();
     for (JInternalFrame frame : frames)
     {
       if (frame instanceof SplitFrame && frame != source)
@@ -3291,24 +3521,99 @@ public class Desktop extends jalview.jbgui.GDesktop
 
   public static groovy.ui.Console getGroovyConsole()
   {
-    return groovyConsole;
+    Desktop desktop = Desktop.getInstance();
+    return desktop == null ? null : desktop.groovyConsole;
   }
 
-  public static void transferFromDropTarget(List<String> files,
+  /**
+   * handles the payload of a drag and drop event.
+   * 
+   * TODO refactor to desktop utilities class
+   * 
+   * @param files
+   *          - Data source strings extracted from the drop event
+   * @param protocols
+   *          - protocol for each data source extracted from the drop event
+   * @param evt
+   *          - the drop event
+   * @param t
+   *          - the payload from the drop event
+   * @throws Exception
+   */
+  @SuppressWarnings("unchecked")
+  public static void transferFromDropTarget(List<Object> files,
           List<DataSourceType> protocols, DropTargetDropEvent evt,
           Transferable t) throws Exception
   {
 
+    // BH 2018 changed List<String> to List<Object> to allow for File from SwingJS
+
+    // DataFlavor[] flavors = t.getTransferDataFlavors();
+    // for (int i = 0; i < flavors.length; i++) {
+    // if (flavors[i].isFlavorJavaFileListType()) {
+    // evt.acceptDrop(DnDConstants.ACTION_COPY_OR_MOVE);
+    // List<File> list = (List<File>) t.getTransferData(flavors[i]);
+    // for (int j = 0; j < list.size(); j++) {
+    // File file = (File) list.get(j);
+    // byte[] data = getDroppedFileBytes(file);
+    // fileName.setText(file.getName() + " - " + data.length + " " +
+    // evt.getLocation());
+    // JTextArea target = (JTextArea) ((DropTarget) evt.getSource()).getComponent();
+    // target.setText(new String(data));
+    // }
+    // dtde.dropComplete(true);
+    // return;
+    // }
+    //
+
     DataFlavor uriListFlavor = new DataFlavor(
-            "text/uri-list;class=java.lang.String");
+            "text/uri-list;class=java.lang.String"), urlFlavour = null;
+    try
+    {
+      urlFlavour = new DataFlavor(
+              "application/x-java-url; class=java.net.URL");
+    } catch (ClassNotFoundException cfe)
+    {
+      Cache.log.debug("Couldn't instantiate the URL dataflavor.", cfe);
+    }
+
+    if (urlFlavour != null && t.isDataFlavorSupported(urlFlavour))
+    {
+
+      try
+      {
+        java.net.URL url = (URL) t.getTransferData(urlFlavour);
+        // nb: java 8 osx bug https://bugs.openjdk.java.net/browse/JDK-8156099
+        // means url may be null.
+        if (url != null)
+        {
+          protocols.add(DataSourceType.URL);
+          files.add(url.toString());
+          Cache.log.debug("Drop handled as URL dataflavor "
+                  + files.get(files.size() - 1));
+          return;
+        }
+        else
+        {
+          if (Platform.isAMacAndNotJS())
+          {
+            System.err.println(
+                    "Please ignore plist error - occurs due to problem with java 8 on OSX");
+          }
+        }
+      } catch (Throwable ex)
+      {
+        Cache.log.debug("URL drop handler failed.", ex);
+      }
+    }
     if (t.isDataFlavorSupported(DataFlavor.javaFileListFlavor))
     {
       // Works on Windows and MacOSX
       Cache.log.debug("Drop handled as javaFileListFlavor");
-      for (Object file : (List) t
+      for (Object file : (List<Object>) t
               .getTransferData(DataFlavor.javaFileListFlavor))
       {
-        files.add(((File) file).toString());
+        files.add(file);
         protocols.add(DataSourceType.FILE);
       }
     }
@@ -3328,63 +3633,115 @@ public class Desktop extends jalview.jbgui.GDesktop
         // fallback to text: workaround - on OSX where there's a JVM bug
         Cache.log.debug("standard URIListFlavor failed. Trying text");
         // try text fallback
-        data = (String) t.getTransferData(
-                new DataFlavor("text/plain;class=java.lang.String"));
-        if (Cache.log.isDebugEnabled())
+        DataFlavor textDf = new DataFlavor(
+                "text/plain;class=java.lang.String");
+        if (t.isDataFlavorSupported(textDf))
         {
-          Cache.log.debug("fallback returned " + data);
+          data = (String) t.getTransferData(textDf);
         }
+
+        Cache.log.debug("Plain text drop content returned "
+                + (data == null ? "Null - failed" : data));
+
       }
-      while (protocols.size() < files.size())
-      {
-        Cache.log.debug("Adding missing FILE protocol for "
-                + files.get(protocols.size()));
-        protocols.add(DataSourceType.FILE);
-      }
-      for (java.util.StringTokenizer st = new java.util.StringTokenizer(
-              data, "\r\n"); st.hasMoreTokens();)
+      if (data != null)
       {
-        added = true;
-        String s = st.nextToken();
-        if (s.startsWith("#"))
-        {
-          // the line is a comment (as per the RFC 2483)
-          continue;
-        }
-        java.net.URI uri = new java.net.URI(s);
-        if (uri.getScheme().toLowerCase().startsWith("http"))
+        while (protocols.size() < files.size())
         {
-          protocols.add(DataSourceType.URL);
-          files.add(uri.toString());
+          Cache.log.debug("Adding missing FILE protocol for "
+                  + files.get(protocols.size()));
+          protocols.add(DataSourceType.FILE);
         }
-        else
+        for (java.util.StringTokenizer st = new java.util.StringTokenizer(
+                data, "\r\n"); st.hasMoreTokens();)
         {
-          // otherwise preserve old behaviour: catch all for file objects
-          java.io.File file = new java.io.File(uri);
-          protocols.add(DataSourceType.FILE);
-          files.add(file.toString());
+          added = true;
+          String s = st.nextToken();
+          if (s.startsWith("#"))
+          {
+            // the line is a comment (as per the RFC 2483)
+            continue;
+          }
+          java.net.URI uri = new java.net.URI(s);
+          if (uri.getScheme().toLowerCase().startsWith("http"))
+          {
+            protocols.add(DataSourceType.URL);
+            files.add(uri.toString());
+          }
+          else
+          {
+            // otherwise preserve old behaviour: catch all for file objects
+            java.io.File file = new java.io.File(uri);
+            protocols.add(DataSourceType.FILE);
+            files.add(file.toString());
+          }
         }
       }
+
       if (Cache.log.isDebugEnabled())
       {
         if (data == null || !added)
         {
-          Cache.log.debug(
-                  "Couldn't resolve drop data. Here are the supported flavors:");
-          for (DataFlavor fl : t.getTransferDataFlavors())
+
+          if (t.getTransferDataFlavors() != null
+                  && t.getTransferDataFlavors().length > 0)
           {
             Cache.log.debug(
-                    "Supported transfer dataflavor: " + fl.toString());
-            Object df = t.getTransferData(fl);
-            if (df != null)
-            {
-              Cache.log.debug("Retrieves: " + df);
-            }
-            else
+                    "Couldn't resolve drop data. Here are the supported flavors:");
+            for (DataFlavor fl : t.getTransferDataFlavors())
             {
-              Cache.log.debug("Retrieved nothing");
+              Cache.log.debug(
+                      "Supported transfer dataflavor: " + fl.toString());
+              Object df = t.getTransferData(fl);
+              if (df != null)
+              {
+                Cache.log.debug("Retrieves: " + df);
+              }
+              else
+              {
+                Cache.log.debug("Retrieved nothing");
+              }
             }
           }
+          else
+          {
+            Cache.log.debug("Couldn't resolve dataflavor for drop: "
+                    + t.toString());
+          }
+        }
+      }
+    }
+    if (Platform.isWindowsAndNotJS())
+    {
+      Cache.log.debug("Scanning dropped content for Windows Link Files");
+
+      // resolve any .lnk files in the file drop
+      for (int f = 0; f < files.size(); f++)
+      {
+        String source = files.get(f).toString().toLowerCase();
+        if (protocols.get(f).equals(DataSourceType.FILE)
+                && (source.endsWith(".lnk") || source.endsWith(".url")
+                        || source.endsWith(".site")))
+        {
+          try
+          {
+            Object obj = files.get(f);
+            File lf = (obj instanceof File ? (File) obj
+                    : new File((String) obj));
+            // process link file to get a URL
+            Cache.log.debug("Found potential link file: " + lf);
+            WindowsShortcut wscfile = new WindowsShortcut(lf);
+            String fullname = wscfile.getRealFilename();
+            protocols.set(f, FormatAdapter.checkProtocol(fullname));
+            files.set(f, fullname);
+            Cache.log.debug("Parsed real filename " + fullname
+                    + " to extract protocol: " + protocols.get(f));
+          } catch (Exception ex)
+          {
+            Cache.log.error(
+                    "Couldn't parse " + files.get(f) + " as a link file.",
+                    ex);
+          }
         }
       }
     }
@@ -3399,4 +3756,42 @@ public class Desktop extends jalview.jbgui.GDesktop
   {
     Cache.setProperty(EXPERIMENTAL_FEATURES, Boolean.toString(selected));
   }
+
+  /**
+   * Answers a (possibly empty) list of any structure viewer frames (currently for
+   * either Jmol or Chimera) which are currently open. This may optionally be
+   * restricted to viewers of a specified class, or viewers linked to a specified
+   * alignment panel.
+   * 
+   * @param apanel
+   *          if not null, only return viewers linked to this panel
+   * @param structureViewerClass
+   *          if not null, only return viewers of this class
+   * @return
+   */
+  public List<StructureViewerBase> getStructureViewers(
+          AlignmentPanel apanel,
+          Class<? extends StructureViewerBase> structureViewerClass)
+  {
+    List<StructureViewerBase> result = new ArrayList<>();
+    JInternalFrame[] frames = getAllFrames();
+
+    for (JInternalFrame frame : frames)
+    {
+      if (frame instanceof StructureViewerBase)
+      {
+        if (structureViewerClass == null
+                || structureViewerClass.isInstance(frame))
+        {
+          if (apanel == null
+                  || ((StructureViewerBase) frame).isLinkedWith(apanel))
+          {
+            result.add((StructureViewerBase) frame);
+          }
+        }
+      }
+    }
+    return result;
+  }
+
 }