Hey all. All works, except for my Aktionsmenü. There is only a black screen. How can I turn it back on???
You recently installed GravityBox wich you can - among other things - use to change the action menu aka quick setting menu.
Open GravityBox go to Statusbar tweaks >QuickSettings management and switch off the “Master switch” to get back to normal, or leave it and use the other options there to customize the QuickSettings.