X-Git-Url: http://source.jalview.org/gitweb/?a=blobdiff_plain;f=src%2Fjalview%2Fgui%2FAlignFrame.java;h=2c7837f077330c11de4bc4538add14c765a28b9c;hb=fd8dc2879b13709703b57dd7ed4b3754b253e12f;hp=ae2e44aefa2070e2c72f3b4ae144e9e7746625b3;hpb=ab67e99fb7336d0f4411488d9f843c720ab6b418;p=jalview.git

diff --git a/src/jalview/gui/AlignFrame.java b/src/jalview/gui/AlignFrame.java
index ae2e44a..2c7837f 100644
--- a/src/jalview/gui/AlignFrame.java
+++ b/src/jalview/gui/AlignFrame.java
@@ -1885,7 +1885,9 @@ public class AlignFrame extends GAlignFrame implements DropTargetListener,
       hiddenColumns = new ArrayList<>();
       int hiddenOffset = viewport.getSelectionGroup().getStartRes();
       int hiddenCutoff = viewport.getSelectionGroup().getEndRes();
-      for (int[] region : viewport.getAlignment().getHiddenColumns())
+      ArrayList<int[]> hiddenRegions = viewport.getAlignment()
+              .getHiddenColumns().getHiddenColumnsCopyAsList();
+      for (int[] region : hiddenRegions)
       {
         if (region[0] >= hiddenOffset && region[1] <= hiddenCutoff)
         {