From 8240aa86ee94d4c372af7deb1452a8294ff8800b Mon Sep 17 00:00:00 2001
From: amwaterhouse <Andrew Waterhouse>
Date: Tue, 3 Oct 2006 09:18:22 +0000
Subject: [PATCH] Check on vscrollMax values

---
 src/jalview/appletgui/AlignmentPanel.java |   15 +++++++++------
 1 file changed, 9 insertions(+), 6 deletions(-)

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
     {
-- 
1.7.10.2