Demetra/5.1.1 GUI designer hangs after

I can't edit UI form. :) In Demetra, or in 5.1.1. After I've done something (nothing special, only opened a form in Demetra and dragged/clicked some times/tried to take some screenshots of funny listener face), now I can do nothing with UI form. After I open it, Idea freezes and stops responding completely.

Also, I've some Components in Default palette (JSeparator, JToolBar, JScrollBar, etc) - with default, "green alien" icons (in 5.1.1), may be something there corrupted?

After changing default layout manager from GridLayoutManager to FlowLayout, everything is ok. Wow. Cool. Back to work again!