Why does the home screen stay empty (no application icons/no widgets) sometimes? I have a Motorola Milestone, and sometimes when I press Home to go back to the Home Screen, the screen shows no application icons, no widgets.

It simply stays blank, with the wallpaper on background. I can navigate to the other Home Screens by dragging to left or right, but every screen it empty.

The phone seems normal, no slowness, the app drawer opens up normally.

The only solution I thought was to restart the phone. I don't use any task killer.

I also noticed this started to happen recently, after installing many applications. And it normally happens after running some heavy app, like Angry Birds.

Did anyone notice this too?
The Milestone (original Motorola Droid to all you Americans) doesn't use the default home screen app because of the slide out keyboard, since the default home screen app doesn't support landscape.  Switching to one of the other alternate home screen apps might solve your problem.