Here's a comment that may or may not be useful when this bug is being fixed:

Locally, I had a go at fixing this by changing the implementation of ModuleController.getSelectedNode() to the following:

    public JMeterTreeNode getSelectedNode()
    {
    	if (selectedNode == null)
    	{
    		restoreSelected();
    	}
        return selectedNode;
    }


Although I believe that means the node being referenced must come before the ModuleController referencing it, this seemed to do the trick.

I subsequently came across another problem:

If the Node (Module) being referenced has a sub Node (A HTTPSampler say) with the same name e.g.

Test Plan
 |--- Modules
 |     |--- Hit Search Page
 |           |--- Hit Search Page
 |--- Thread Group
 |     |--- Module Controller (Points to Modules -> Hit Search Page)

Then the traverse method will fall over resulting in the user being given a "0 >= 0" dialog box (exception has no stack either).

Im afraid I have no real solution to suggest (apart from maybe giving each node an id that isn't the name), but the work around is to ensure that Sub components/nodes of a referenced module do not share that module's name.