xul - window resize

Hi.
I have problem with resizing window element. I would like to create two views of my app - one rolled into bar (300x50) and standard (300x500).
When I try to use window.resizeTo to shrink window I have strange result - half of my window is not visible.
When I force os to repaint - using alt+tab or other method everything start to look as it should. But each window resize ends up same way - part of window is not visible until repain. How to force this repain? 

I've tried requestAnimationFrame, sizeToContent and nothing seems to help.

please help! :)