Insensitivity for touch events, as long as screen will not be restarted

On some android devices after switching to new activity I could not get any touch event as long as I turn off and on screen.

I have noticed this on Xperia X10 and Motorola Milestone 2. After launching second activity I could not press any button, expand a list and so forth.. however I can do that, if screen get time out in meantime or I turn off and turn on it manually.

My questions are...

What 开发者_如何学Gocan cause insensitivity for touch events? What actions are happens after restart of a screen...

Maybe with this informations I will be able to figure out where is my problem.