X-Git-Url: http://source.jalview.org/gitweb/?a=blobdiff_plain;f=src%2Fjalview%2Fappletgui%2FAlignmentPanel.java;h=414717782c836398a92eb91c4ec3532372bd9d56;hb=ddbcb3e33e1a8d4c644472cfa3d28b193da97064;hp=f8f31b26e7c896e91d68027efb03e5cef78529f0;hpb=e54df488cd82761bfb0e9372aeae2acc5a1324d7;p=jalview.git

diff --git a/src/jalview/appletgui/AlignmentPanel.java b/src/jalview/appletgui/AlignmentPanel.java
index f8f31b2..4147177 100644
--- a/src/jalview/appletgui/AlignmentPanel.java
+++ b/src/jalview/appletgui/AlignmentPanel.java
@@ -817,14 +817,14 @@ public class AlignmentPanel extends Panel implements AdjustmentListener,
       {
         return;
       }
-      else if (newY > -1)
+      if (newY > -1)
       {
         /*
          * limit page up/down to one width's worth of positions
          */
         int rowSize = vpRanges.getViewportWidth();
         int newX = newY > oldY ? oldX + rowSize : oldX - rowSize;
-        vpRanges.setViewportStartAndWidth(newX, rowSize);
+        vpRanges.setViewportStartAndWidth(Math.max(0, newX), rowSize);
       }
     }
     else