Index: /trunk/autoquest-ui-swt/src/main/java/de/ugoe/cs/autoquest/ui/swt/ShowGuiModelDialog.java
===================================================================
--- /trunk/autoquest-ui-swt/src/main/java/de/ugoe/cs/autoquest/ui/swt/ShowGuiModelDialog.java	(revision 1260)
+++ /trunk/autoquest-ui-swt/src/main/java/de/ugoe/cs/autoquest/ui/swt/ShowGuiModelDialog.java	(revision 1261)
@@ -191,7 +191,13 @@
         
         // update visualization of the model
-        firstParent.removeAll();
-        buildGuiTree(firstParent, model.getTraverser((IGUIElement) firstParent.getData()));
-        firstParent.setExpanded(true);
+        if (firstParent != null) {
+            firstParent.removeAll();
+            buildGuiTree(firstParent, model.getTraverser((IGUIElement) firstParent.getData()));
+            firstParent.setExpanded(true);
+        }
+        else {
+            guiTree.removeAll();
+            buildGuiTree();
+        }
     }