diff -ruN oregano-0.69.0/src/sheet/sheet-item.c oregano-0.69.0_patched/src/sheet/sheet-item.c
--- oregano-0.69.0/src/sheet/sheet-item.c	2007-08-14 08:05:34.000000000 +0200
+++ oregano-0.69.0_patched/src/sheet/sheet-item.c	2008-08-17 22:38:41.000000000 +0200
@@ -595,7 +595,12 @@
 
 				item_data = SHEET_ITEM (list->data)->priv->data;
 				item_data_move (item_data, &delta);
-				item_data_register (item_data);
+				//item_data_register (item_data);
+				if (item_data_register(item_data) == -1) {
+					/* Merged item needs to be deleted */
+					g_object_unref (G_OBJECT (item_data));
+					gtk_object_destroy(GTK_OBJECT(list->data));
+				}
 			}
 
 			break;