N9 swipe to close (up-to-down) not working. Also top toolbar cannot be accessed anymore...
 

Hi all.
It seems that the swipe to close is not working anymore. When I try to close an open app and move my finger downwards from the top it seems not to recognize my touch on the status bar part of the screen. But the app itself acknowledges my action but does nothing.
Also the touching of the status bar and opening of the task bar with volumes control and connectivity does not work.
There are moments when things seem to return to normal but happen random and do not last.

Any ideas?