diff -r 82bca69d8d37 -r 89366181efd9 DataSetBuilder.st
--- a/DataSetBuilder.st	Thu Feb 05 21:59:12 1998 +0100
+++ b/DataSetBuilder.st	Thu Feb 05 22:08:34 1998 +0100
@@ -2259,6 +2259,7 @@
 
     |label list|
 
+    self checkMenuItemModified ifFalse: [^nil].
     list := self seqList.
     label := self class clipboard label.
     columns add: self class clipboard deepCopy afterIndex:selectedColumnIndex.