Flicker(?) in Applet

[amitdev]

I have an applet, which internally uses a JFrame. Now, sometimes a new
JFrame will be opened from the existing one (for wizard etc).
The problem is on certain workflows, the two windows (JFrame's)
start considerable flickering (or switching between the two windows
continously). There is no way to stop this except minimizing the
two and start again.
Scenarios when it happens:
1. The two JFrames have menus. I select on Menu on one window and
click on the next windows menu.
2. From one JFrame, lets say the user clicks on wizard. If I show the
wizard's JFrame it works fine. But if I put a JOptionPane to ask
whether 'you really want to open wizard' and then open the JFrame, the
flickering starts.

Anybody seen similar problems? Is it a Java bug?
I'm using 1.2

Thanks
aMit