Ideas for revised UI
Tabbed interface with the buttons working as tabs. No nested menus. All windows are shown in the main one, no open floating windows.
Main connection overview
Settings Group and search bar shown by default, can be turned off in Settings tab. Debugging not shown by default, can be turned on in Settings tab. Use as default remote desktop client
Plugins Available by default, can be turned off in settings.
Debugging Available button to be turned on in settings.
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"Quit" removed in favour of clicking [x] or Alt+F4