Enables proximity sensor - no input function during call

Film was good to install, but unfortunately you will activate the proximity sensor. That is, the film suggests the display when a call is an approximation (eg the ear), provides the display black and no input options are no longer present. You have to wait almost until the called party hangs up, because you yourself have no way to influence or to end the call.
The first thought was, of course, that something had broken down at the Nexus 4, as the screen remained black. After I've read in relevant forums of the film problem I removed them unceremoniously back and immediately the full operability was given again.
Therefore, unfortunately, only one out of five stars.