[Stylesheet] ProDark: major bugfix for add-ons
[Stylesheet] ProDark: major bugfix for add-ons

https://forum.freecadweb.org/viewtopic.php?f=34&t=55134&start=100

Fat-Zer/FreeCAD_sf_master,Fat-Zer/FreeCAD_sf_master,Fat-Zer/FreeCAD_sf_master,Fat-Zer/FreeCAD_sf_master,Fat-Zer/FreeCAD_sf_master