The PGF GWT module needs to inherit the DnD stuff.

src/server/gwt/src/se/chalmers/cs/gf/gwt/FridgeApp.gwt.xml

@@ -13,9 +13,6 @@
       <!-- <inherits name="com.google.gwt.user.theme.dark.Dark"/>     -->
 
       <!-- Other module inherits                                      -->
-      
-      <!-- Inherit gwt-dnd support                   -->
-      <inherits name='com.allen_sauer.gwt.dnd.gwt-dnd'/>
 
 
       <!-- Specify the app entry point class.                         -->

src/server/gwt/src/se/chalmers/cs/gf/gwt/PGF.gwt.xml

@@ -5,4 +5,7 @@
       <inherits name="com.google.gwt.http.HTTP" />
       <inherits name="com.google.gwt.json.JSON" />
 	
+	  <!-- Inherit gwt-dnd support                   -->
+      <inherits name='com.allen_sauer.gwt.dnd.gwt-dnd'/>
+	
 </module>