Editor colors looks wrong

While I was developing in C++ and noticed that every time I "accidentally" change font size by holding Shift+Control and mouse while or Mac Book Pro trackpad font size changes but when I switch to another open cpp or header file their colors are not refreshed. By changing font in current buffer fixes the repaint but now ma thing when I switch to any open buffers.

I am running in Parallels VM (ubuntu guest) on Mac 10.10.3 (host). So that is why accidentally since Shift+Control is also used for other VM/Host navigations.

Also I think it would be good to place soon combo box somewhere like Visual Studio does so user can see his zoom level from Preferences settings. Also he should be able to select 100% and go back to what was set in QT Creator Preferences as default size