Bug#952972: cinnamon: windows (desklets?) at the back capturing clicks from front windows

[cacatoes@tuxfamily.org]

Package: cinnamon
Version: 3.8.8-1

Hello Dear Maintainers,

Several users seem to experience weirdness with mouse clicks with
Cinnamon, this problem may have been around for years[1]. I'm still
unsure of the origin, I suspect the culprit may be related to the
«Desklets» feature. I kinda manage to reproduce it.

It happens both on Debian Stable, and Debian Testing.

So, here is the setup:

- Have the «Notes» (@schlorri) Desklet running on the Desktop. Customize
  it to use some text editor like gedit. Put this desklet to the center
  of the screen.
- Run gnome-terminal. Put this terminal to the center of the screen in
  front of the desklet.
- Run nemo file-manager, windowed not fullscreen, in front of the 2
  other windows.
- Now, minimize Nemo to taskbar, and quickly click (eventually
  double-click, this might exhibit the behaviour more often) on
  the center of the screen (that is, on the terminal) during the
  minimize animation.

What will happen:
- gedit will popup, although the desklet was not on the
front. Or, 
- the Note desklet will be in "move window" mode, even though mouse
  button has been released.

You might have to repeat step 4 a few times to manage to get this
improper behaviour.

Regards,

[1]: https://forums.linuxmint.com/viewtopic.php?f=208&t=237811