Why the changes to the 18.04 desktop?

[Paul Smith]

On Mon, 2020-10-19 at 17:08 +0200, Liam Proven wrote:
> On Mon, 19 Oct 2020 at 16:49, Paul Smith <paul at mad-scientist.net>
> wrote:
> > That means when you press Alt followed by SPACE and C, the computer
> > will see a two-key combination: either Alt-SPACE Alt-C or Alt-C
> > Alt-SPACE.
> 
> You are misreading the OP's description, I presume out of lack of
> familiarity with the Microsoft windows-control menu which has been in
> Windows since the beginning (~November 1985) and in xNix since the
> Motif toolkit and  window manager (July 1989).

Possibly, combined with a lack of specificity in the question.

So, the problem is not about combining these keys at all.  The issue is
that "C" is not set as a hotkey for Close in the window control menu.