title: Ubuntu: Nvidia Applet disappeared after switching to Intel Graphics
body: <p>I am using Ubuntu 20.04 Mate. And I had some trouble getting my external Display to work via HDMI, therefor I tried switching from nvidia graphics to intel graphics using the applet in my Desktop Panel.
  Now I can't switch back to Nvidia since the Applet Icon disappeared. I tried checking the Nvidia Settings, but it shows just an empty window. The Nvidia Card worked perfectly till now. How can I reactivate it?</p>