So... my friend has a german version of N900. T-mobile i think.
When he recieves a call with phone on the table, its all ok.

But when its somewhere in pocket, when pulled out it is not showing incoming call screen and to see it, must open keyboard. So no other possability to answer call.

P.S.
latest avaiable FW

Any sugestions?

Enyone?

Ok... this device is only one with this bug

Mine is sluggish in this two. Did you install the app to prevent accidental answering (forgotten its name but search for it)?
Also, the auto-rotate feature causes some lag when you try to answer.

It may be that the proximity sensor is covered or has something over it. Check the manual/forums about the proximity sensor. The "Health check" program in the extras repository can show you what the current state is.

Commonly if the sensor is "closed" (which means something is near it) when the call comes in, it keeps the UI blank, assuming it's in a pocket and doesn't want a stray bump to answer it. When it goes "open" (from coming out of the pocket), the UI turns on. But if the sensor is not detecting properly, and is always "closed", that could cause exactly what you're seeing. Could be anything from some smudge on the glass over the sensor, to a glaring screen protector, to a faulty sensor.