Bug#822697: qt5 apps in gnome do not use the gtk style as they should

[Vladimir K]

This bug may be closed now as gtk2 style is packaged in qt5-style-plugins.

With this package installed and the following vars in the environment Qt now 
correctly renders GTK themes.
  QT_STYLE_OVERRIDE=gtk2
  QT_QPA_PLATFORMTHEME=gtk2