Index: /trunk/autoquest-core-events/src/main/java/de/ugoe/cs/autoquest/eventcore/guimodel/GUIModel.java
===================================================================
--- /trunk/autoquest-core-events/src/main/java/de/ugoe/cs/autoquest/eventcore/guimodel/GUIModel.java	(revision 1115)
+++ /trunk/autoquest-core-events/src/main/java/de/ugoe/cs/autoquest/eventcore/guimodel/GUIModel.java	(revision 1116)
@@ -17,4 +17,5 @@
 import java.io.OutputStream;
 import java.io.PrintStream;
+import java.io.Serializable;
 import java.io.UnsupportedEncodingException;
 import java.util.ArrayList;
@@ -37,5 +38,8 @@
  * @author Patrick Harms, Steffen Herbold
  */
-public class GUIModel {
+public class GUIModel implements Serializable {
+
+    /**  */
+    private static final long serialVersionUID = 1L;
 
     /**
@@ -460,5 +464,5 @@
         treeNode1.guiElement.addEqualGUIElement(treeNode2.guiElement);
         treeNode2.guiElement.addEqualGUIElement(treeNode1.guiElement);
-
+        
         // and now a replacement node that is the merge of treeNode1 and treeNode2 is created
         TreeNode replacement = new TreeNode();
@@ -748,5 +752,8 @@
      * @author Patrick Harms, Steffen Herbold
      */
-    private class TreeNode {
+    private class TreeNode implements Serializable {
+
+        /**  */
+        private static final long serialVersionUID = 1L;
 
         /**