diff --git a/ChangeLog b/ChangeLog
index 0320fe32c..72cec0e64 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,3 +1,8 @@
+2010-04-24 Doug Simons <doug.simons@testplant.com>
+
+	* Source/NSOutlineView.m:
+	Fix occasional exception while dragging.
+
 2010-04-24 Doug Simons <doug.simons@testplant.com>
 
 	* Source/NSWindow.m:
diff --git a/Source/NSOutlineView.m b/Source/NSOutlineView.m
index c000f5568..e13640e89 100644
--- a/Source/NSOutlineView.m
+++ b/Source/NSOutlineView.m
@@ -1359,7 +1359,7 @@ Also returns the child index relative to this parent. */
       /* If we have been hovering over an item for more than half a second,
        * we should expand it.
        */
-      if ([lastDragUpdate timeIntervalSinceDate: lastDragChange] >= 0.5)
+      if (lastDragChange != nil && [lastDragUpdate timeIntervalSinceDate: lastDragChange] >= 0.5)
 	{
 	  id item = [_items objectAtIndex: row];
 	  if ([self isExpandable: item] && ![self isItemExpanded: item])