missized emulator window under Linux, J2ME wireless toolkit

I ran into the following problem while evaluating Sun's J2ME Wireless Toolkit under Linux:
The device emulator starts in an not resizalbe Window with the wrong dimensions, ie. the window is MUCH to small. This problem is dependant of the X-WindowManager used:
* this occurs using kwm, icewm or WindowMaker;
* this occures using gnome, but only if the emulator is started out of the ktoolbar, not when started by "emulator &" on the commandline;
* this is NO problem, when using twm
Has anyone any suggestions what's the reason for this behavior and how I can use my favorite windowmanager (icewm) and develop in my favorite programming language (Java) on my favorite OS(Linux)? Thank You such much for your respond!
Linux: SuSE 7.3
Java: Sun J2SE 1.3.1
J2ME: Sun J2ME Wireless Toolkit 1.3.0