1. An apparatus comprising: an overlap detector configured to determine if a first image superimposed with a second image overlaps an object in the second image by greater than a threshold; and a display modification unit configured to change the content of the first image superimposed with the second image such that the first image no longer overlaps the object in the second image by greater than the threshold when the overlap detector detects that the first image overlaps the object in the second image by greater than the threshold.