Java SE (Java Platform, Standard Edition)

I've been seeing a intermittently-reproducible problem with some of my buttons recently.

I have a button that I created by passing in a simple action, e.g.

...
JButton runButton = new JButton(new RunAction()); 
...

public class RunAction extends AbstractAction
	{
          System.err.println("action!");
          // do something
        }

The button is part of a simulation that is doing a lot of work and spending lots of time painting, so is probably putting a lot of weight on the event-dispatching(?) thread.

The problem is that when the simulation is running, I fairly frequently find that I can push the button, see the button change in the UI, and yet the RunAction is not called (which I can tell because it should print something to standard error).

My questions are:

1) Does it make sense that I might see the button get pressed (so something knew it was clicked), but the button's action doesn't get called?

2) How can I prevent this from happening?

Note that this appears to only happen on Windows (Vista) -- I haven't seen this on my Mac.

Thanks!