I've added a ControlNode containing a JButton to my Diagram.

When I first load the diagram everything is fine (loadFromXML() is called and returns).

However if I make a change, save the diagram (to XML, which is stored in a database) then call loadFromXML() the call does not return, and does not write any logging details I can find. I have to kill my applet.

Have you any ideas about why this might be happening? What I can do to prevent it?

Copy of the XML (in a text file) is attached in case that tells you anything (I have removed some images, but these don't cause the problem as I have used them without problems on other diagrams)

I'm running the applet within the 'applet viewer' of my IDE (IntelliJ IDEA) and I believe all logging which would normally go to the plug-in console is displayed in the IDE console - and there is nothing written there

Task Manager indicates that the 'applet' process is using 190896K of private working memory after several minutes of 'hanging', when I finally decide to kill it. This memory usage doesn't seem excessive to me.

I am using Java 1.7 (64bit) to run the applet.

A diagram without the button, even with quite a lot of nodes and links causes no problems.

A diagram with the button, only 2 nodes and no links fails to load from XML as previously described.

I use Log4j for logging - is there any logging I can 'turn on' for JDiagram that might help us track down the problem?

Yes your link worked fine.

The diagram is hosted within an applet which does a lot of other things too.

I'll try putting the 'change view' functionality elsewhere as you suggest - all diagrams (subject to data availability) need to support 'change view' and any given diagram can change whether 'change view' is supported if the user changes some data!!