X-Git-Url: http://source.jalview.org/gitweb/?a=blobdiff_plain;f=src%2Fjalview%2Fappletgui%2FAlignmentPanel.java;h=da55119dcc620accf96010a27ba8a2d4065cb238;hb=32af8b07a990ff91665e7975bc4139133ea9f5e7;hp=bcdffa095f04cd590a4f0aa227c7f33e81cbf84f;hpb=502eab512b790bcee60cefef90b0c46711a4264d;p=jalview.git

diff --git a/src/jalview/appletgui/AlignmentPanel.java b/src/jalview/appletgui/AlignmentPanel.java
index bcdffa0..da55119 100755
--- a/src/jalview/appletgui/AlignmentPanel.java
+++ b/src/jalview/appletgui/AlignmentPanel.java
@@ -489,13 +489,16 @@ public class AlignmentPanel extends Panel implements AdjustmentListener
       if (av.hasHiddenColumns)
         maxwidth = av.getColumnSelection().findColumnPosition(maxwidth) - 1;
 
-      int max = maxwidth /
-          seqPanel.seqCanvas.getWrappedCanvasWidth(seqPanel.seqCanvas.getSize().width) +
-          1;
+      int canvasWidth = seqPanel.seqCanvas.getWrappedCanvasWidth
+          (seqPanel.seqCanvas.getSize().width);
 
-      vscroll.setMaximum(max);
-      vscroll.setUnitIncrement(1);
-      vscroll.setVisibleAmount(1);
+      if(canvasWidth>0)
+      {
+        int max = maxwidth / canvasWidth;
+        vscroll.setMaximum(max);
+        vscroll.setUnitIncrement(1);
+        vscroll.setVisibleAmount(1);
+      }
     }
     else
     {