JAL-3127 check for null viewport

diff --git a/src/jalview/schemes/ClustalxColourScheme.java b/src/jalview/schemes/ClustalxColourScheme.java
index b1cfe82..19723ca 100755 (executable)
--- a/src/jalview/schemes/ClustalxColourScheme.java
+++ b/src/jalview/schemes/ClustalxColourScheme.java
@@ -340,7 +340,7 @@ public class ClustalxColourScheme extends ResidueColourScheme
           AnnotatedCollectionI sg)
   {
     ClustalxColourScheme css = new ClustalxColourScheme(sg,
-            view.getHiddenRepSequences());
+            view == null ? null : view.getHiddenRepSequences());
     css.includeGaps = includeGaps;
     return css;
   }