check colourscheme is not null

diff --git a/src/jalview/gui/SliderPanel.java b/src/jalview/gui/SliderPanel.java
index f95f84b..1a62fff 100755 (executable)
--- a/src/jalview/gui/SliderPanel.java
+++ b/src/jalview/gui/SliderPanel.java
@@ -232,6 +232,11 @@ public class SliderPanel
       if (allGroups != null)\r
       {\r
         toChange = ( (SequenceGroup) allGroups.get(groupIndex)).cs;\r
+        if(toChange==null)\r
+        {\r
+          groupIndex--;\r
+          continue;\r
+        }\r
       }\r
 \r
       if (forConservation)\r