In Delphi 10.3 I added a GExperts Dock Window, docked a few Tool Panels to it and saved the IDE Default Layout. This restored the Dock Window with the Tool Panels after IDE restart. However, this seems not working anymore in Delphi 12: The GExperts Dock Window is not restored after IDE restart!
I've found a partial solution here:
https://www.delphipraxis.net/214041-gexperts-dock-window-delphi-12-a.html