I have had rather similar problems before, but with a different sort of app.
The
Java tutorial has a "common problems" page, so I looked there. I tried things to speed up processing, as suggested in the tutorial, including changing all my doubles to floats.
I tried opacifying the content pane, but still had problems.
I tracked it down to a method which was applying an affine transform to the Graphics2D object. Without the transform the method took 1.6 microseconds to run, with, it was much slower, over 50 microseconds, but the same method run a 2nd time was faster, about 8 microseconds.
That delay was obviously what caused my problems.
Eventually I sorted it out by setting up a Timer to repaint() the whole things repeatedly. A cheat's workaround maybe, but it worked.
Have you got anything like that? Go through all your methods with the System.nanoTime() method and see if you can find such a delay.
Put System.out.print() calls into every method, and follow their sequence. Have you got any loops where your control is recirculating?
When you drag your window, does it remain visible? Have you tried that method which turns your window into an outline when you drag it?
That's all I can suggest. Maybe somebody else will have a better idea.
