patch for JAL-700

diff --git a/src/jalview/datamodel/Alignment.java b/src/jalview/datamodel/Alignment.java
index 1a0d82c..42559c6 100755 (executable)
--- a/src/jalview/datamodel/Alignment.java
+++ b/src/jalview/datamodel/Alignment.java
@@ -143,7 +143,7 @@ public class Alignment implements AlignmentI
    */
   public SequenceI getSequenceAt(int i)
   {
-    if (i < sequences.size())
+    if (i>-1 && i < sequences.size())
     {
       return (SequenceI) sequences.elementAt(i);
     }