X-Git-Url: http://source.jalview.org/gitweb/?a=blobdiff_plain;f=src%2Fjalview%2Fdatamodel%2FHiddenColumns.java;h=da91f7bc86506bb8fcc4ffd49eaf293a8e494432;hb=822ee0479afcc500c72f16b7fa972dc99c8bf5d5;hp=399e083db05599d8ef847850e5a50f24d55bf5a1;hpb=787e3f5f12389d20f4c478d8333f4f459593a8bb;p=jalview.git

diff --git a/src/jalview/datamodel/HiddenColumns.java b/src/jalview/datamodel/HiddenColumns.java
index 399e083..da91f7b 100644
--- a/src/jalview/datamodel/HiddenColumns.java
+++ b/src/jalview/datamodel/HiddenColumns.java
@@ -907,16 +907,19 @@ public class HiddenColumns
     try
     {
       LOCK.writeLock().lock();
-      Iterator<int[]> it = hiddenColumns.iterator();
-      while (it.hasNext())
+      if (hiddenColumns != null)
       {
-        int[] region = it.next();
-        for (int j = region[0]; j < region[1] + 1; j++)
+        Iterator<int[]> it = hiddenColumns.iterator();
+        while (it.hasNext())
         {
-          sel.addElement(j);
+          int[] region = it.next();
+          for (int j = region[0]; j < region[1] + 1; j++)
+          {
+            sel.addElement(j);
+          }
         }
+        hiddenColumns = null;
       }
-      hiddenColumns = null;
     } finally
     {
       LOCK.writeLock().unlock();