Every Android developer knows how challenging it is to properly handle different screen sizes and different permissions. But there are other issues bugging developers. Let’s take an application, which works and looks fine on phone Y with resolution 480×800 and assume that it works & look OK also on phone X with the same resolution. During the testing it becomes clear that on phone X application just crashes at some point although on phone Y it doesn’t happen? And the difference is OS version: Tree View between versions of Android SDK. If your code is based on hard assumptions related to Tree View, you might have a problem.