nullpointer bugfix (another repaint racecondition)

diff --git a/src/jalview/gui/SeqCanvas.java b/src/jalview/gui/SeqCanvas.java
index 77b8938..ad5e052 100755 (executable)
--- a/src/jalview/gui/SeqCanvas.java
+++ b/src/jalview/gui/SeqCanvas.java
@@ -695,7 +695,10 @@ public class SeqCanvas extends JComponent
     {
       nextSeq = av.alignment.getSequenceAt(i);
       if (nextSeq==null)
+      {
+        // occasionally, a race condition occurs such that the alignment row is empty
         continue;
+      }
       sr.drawSequence(nextSeq, av.alignment.findAllGroups(nextSeq),
               startRes, endRes, offset + ((i - startSeq) * av.charHeight));