in my case its not proximity, but yes proximity sensor LOCKs (its not turning off) the screen,example the double tab is working (not only in my case,as we know in N9 we can double tap to unlock screen).so in N9 proximity sensor not turning off but locks the screen,so that the screen in working place,touch ofcourse works

yea i also heard a lot of times about issues accorded to proximity sensor like in this thread [SOLVED] N9 Proximity Sensor - Failure to Reactivate Screen?, but i tried without proximity sensor (unpluged it like as discraibing here (LE55ONS) but not working. I'm strongly confident that its the problem of digitizer or the silicon cover inside of screen,something like that. when i solve it, i put here pics


not at all. the digitizer cable units with silicon cover inside of screen - in theory it can be changed,but i'm afraid in practice 99% impossible as it very kind and hard work. but they are seperated. see the image,uploaded