Every time I left click and hold on my JFrame window, for some reason it just freezes until you let go of the button, I found out that the variables changed using event listeners will freeze, my guess is because of the mouseDragged method. Take a look at the example and see for your self, download is listed below.
Example: FreezeTest.zip *When it says this is not commonly downloaded, that does not mean it's a virus!*