check that we have mappings before trying to broadcast mouseovers involving them

diff --git a/src/jalview/structure/StructureSelectionManager.java b/src/jalview/structure/StructureSelectionManager.java
index d2b336d..9797a20 100644 (file)
--- a/src/jalview/structure/StructureSelectionManager.java
+++ b/src/jalview/structure/StructureSelectionManager.java
@@ -343,7 +343,10 @@ public class StructureSelectionManager
       if (listeners.elementAt(i) instanceof StructureListener)
       {
         sl = (StructureListener) listeners.elementAt(i);
-
+        if (mappings==null)
+        {
+          continue;
+        }
         for (int j = 0; j < mappings.length; j++)
         {
           if (mappings[j].sequence == seq