Spectacle + emacs full screen

[inkbottle <inkbottle007@gmail.com>]

I don't know if the following is relevant...

My emacs version is: 27.0.50, compiled from sources.
I use emacs in full screen mode namely with:
(toggle-frame-fullscreen)
in my dot-emacs.
In fullscreen mode, I don't have access to the panel, where my Spectacle 
widget is.
And my purpose is to take a screenshot of emacs.
Also Spectacle is configured so that it doesn't show any dialogue window, but 
instead goes directly to "select an area and then press enter; and then save 
the image silently; and go away".
So I go on "konsole" (so I have access to the panel), then click on Spectacle, 
then do "Alt-Tab".

First issue, I should be over emacs window, but it still shows me konsole 
window. (I've got a thumbnails column of all my windows when doing Alt-Tab, so 
I know I should be over emacs, but it doesn't show).

Then it tells me that I can press Escape, to leave.

But after doing so, it seems I have no mean to do actually anything anymore: 
plasma session is inaccessible (Alt-tab, or moving the mouse the the upper-
left corner have no effect anymore; pressing "escape", or "enter" neither), 
and I can't leave Spectacle.

Only solution I've found: go in another tty and do a killall spectacle.

And when I come back, emacs which was originally "divided in two", isn't 
anymore, so it's been tampered during the operation.

I don't know if that would be reproducible with a debian's version of emacs.

Thanks,
Chris