I've twice found that when using the COVENANTS addon to Metacreator, I've ended up with the Sort dialogue on top of the window without the least intent to call it and unable to get out of it. If I press OK or Cancel it just flickers and resdiplays the dialogue box. The dialogue is what's called Modal so I can't even get any of the other open windows on top.
Or is it just me? Only seems to happen (so far, touch wood) on my laptop and not my desktop.