Merge branch 'develop' into features/JAL-2094_colourInterface

[jalview.git] / src / jalview / datamodel / Alignment.java

diff --git a/src/jalview/datamodel/Alignment.java b/src/jalview/datamodel/Alignment.java
index fd918fc..2f64759 100755 (executable)
--- a/src/jalview/datamodel/Alignment.java
+++ b/src/jalview/datamodel/Alignment.java
@@ -226,18 +226,21 @@ public class Alignment implements AlignmentI
   {
     if (dataset != null)
     {
+
       // maintain dataset integrity
-      if (snew.getDatasetSequence() != null)
-      {
-        getDataset().addSequence(snew.getDatasetSequence());
-      }
-      else
+      SequenceI dsseq = snew.getDatasetSequence();
+      if (dsseq == null)
       {
         // derive new sequence
         SequenceI adding = snew.deriveSequence();
-        getDataset().addSequence(adding.getDatasetSequence());
         snew = adding;
+        dsseq = snew.getDatasetSequence();
       }
+      if (getDataset().findIndex(dsseq) == -1)
+      {
+        getDataset().addSequence(dsseq);
+      }
+
     }
     if (sequences == null)
     {