I use PHPStorm in In Ubuntu 15.04.
Quite frequently I have encountered problems when opening different dialogs (Find, Commit, etc.) where the content of the dialog is not rendered and just the source editor's background is shown inside the dialog. Here are samples of correct and invalid window. When I close and reopen the window then eventually it comes up correctly.
The same behaviour has been persistent in different PHPStorm versions (10, 2016). I'm using Storm also in Windows 10 in another PC and there I haven't noticed it.