X-Git-Url: http://source.jalview.org/gitweb/?a=blobdiff_plain;f=src%2Fjalview%2Fappletgui%2FOverviewPanel.java;h=ccdfee19d01e9e83148577e723c04abd8f0f7408;hb=950896c0a1a41d799a135f913f438fdc53158093;hp=b3c4a37ffb7e0eea6fbee6ebf4848d0b77e0b166;hpb=abb4c1cc7383a54df59066186eb282588bb884e8;p=jalview.git

diff --git a/src/jalview/appletgui/OverviewPanel.java b/src/jalview/appletgui/OverviewPanel.java
index b3c4a37..ccdfee1 100755
--- a/src/jalview/appletgui/OverviewPanel.java
+++ b/src/jalview/appletgui/OverviewPanel.java
@@ -160,6 +160,14 @@ public class OverviewPanel extends Panel implements Runnable,
    */
   public void updateOverviewImage()
   {
+    if (oviewCanvas == null)
+    {
+      /*
+       * panel has been disposed
+       */
+      return;
+    }
+
     if ((getSize().width > 0) && (getSize().height > 0))
     {
       od.setWidth(getSize().width);
@@ -257,4 +265,21 @@ public class OverviewPanel extends Panel implements Runnable,
     oviewCanvas.resetOviewDims(od);
     updateOverviewImage();
   }
+
+  /**
+   * Removes this object as a property change listener, and nulls references
+   */
+  protected void dispose()
+  {
+    try
+    {
+      av.getRanges().removePropertyChangeListener(this);
+    } finally
+    {
+      av = null;
+      oviewCanvas = null;
+      ap = null;
+      od = null;
+    }
+  }
 }