I have several times had a hildon process hang, drawing 100% CPU. Phone get really warm and runs quickly through the battery.

I can switch between desktops, make phone calls and use running programs.

But I can't start any applications from shortcuts on the desktop, and not interact with any widgets. It is possible to start applications using the menu system. It's just everything on the desktop that is shown but not accessible.

Killing the runaway task - SIGKILL, not SIGTERM - seems to solve the problem.