Hi, I just discovered that it seems impossible to delete VST Instruments at all (I have Cubase 10 / 10.5 / 11).
Even from the Instrument Rack I could not see any option to delete an instrument.
Did I miss something? Please tell me that it is just me and not Cubase / Steinberg!
Ok, from another user in a FB Cubase group I got the solution: SHIFT + DEL on the selected Instrument Track will delete it.
I just don’t see reason behind it. Why would I need another keyboard command to do things which should / must work also in a normal way?
Who is coding these cumbersome stuff? And now I know it is for all tracks the same? I believe in the past it was more easy to remove a track, either by a menu dialog or by just hitting DEL or right click on the/any track and select remove track (I have done this several times). 
Ok, blame me or the universe, why the heck is the “Remove selected track” now all of a sudden visible??? It was not there in the right-click dialog, I swear! I need more drinks I suppose.
Ok, I think I got it. Why I got in such a confusion was initially the missing option in the right-click selection on a track “Remove selected tracks”. Now I figured out the option to start Cubase “as Administrator” (done via the Shortcut on the Desktop) caused trouble within Cubase (tbc).