muffin: cropped shadows on session quit dialog

[SebastJava]

Describe the bug Some windows have all kinds of squared and/or cropped shadows, sometimes

To Reproduce

1. Get a solid white background, just to see those shadows clearly (cinnamon-settings backgrounds > Settings: picture-aspect=No-picture, Background-color=solid-white)
2. Prefer the Mint-Y GTK theme, the light one (cinnamon-settings themes)
3. Menu > Quit
4. See? Not perfect but almost? Try again: Cancel, Menu > Quit.
5. See? Some sort of square shadow (see video and screenshot below).
6. Move the window
7. See, now that's okay. That's how it should always be displayed.
8. Try the same steps above, but with a left side tiled window behind
9. See? A weird, cropped shadow.

Expected behavior I would expect shadows to look like shadows and stay constant when i just move a window that is already focused.

Video captures and screenshots (OPEN IN A NEW TAB, FULL SCREEN to see all the tiny details.)

VM-SquaredShadows-2022-07-19_09.47.33.webm

VM-ShadowOverShadow-2022-07-19_10.02.30.webm

Hardware and mintUpdate

• VM-inxi.txt (VirtualBox+GAs) inxi -Fxxxrz > /media/sf_VirtualBox_Shared/VM-inxi.txt
• Is your system all up-to-date ? YES. (Tue, 19 Jul 2022 09:16:41 -0400)

Additional context

• You also accidentally get to see this other #35 issue again.
• This is easy to reproduce here, but hard to share. When i try to get a screenshot the window gets fixed, approximately, automatically. So, i have to make a video and take screenshots from this video... (video capture from Host with SimpleScreenRecorder) EDIT: I found i can also make screenshots from the VM-host, and i did.
• This is some sort of follow-up to #27, closed too early, IMHO :)

[SebastJava]

• To be sure, i checked, again, mintUpdate is all up-to-date. (I did refresh on approx. Tue, 19 Jul 2022 12:03 -0400)
• Software sources: restore default settings (US+UK mirrors) + update APT cache
• To be sure, i checked, again, mintUpdate is all up-to-date. (I did refresh again on approx. Tue, 19 Jul 2022 12:03 -0400)

[PicoMitchell]

I am also seeing this issue on a fully updated installation of Mint 21 beta on a real PC (not VM) as of 2022-07-19 20:11:49 UTC

I've attached the output of inxi -Fxxxrz: inxi.txt

[SebastJava]

OP update: Prefer the Mint-Y GTK theme, the light one. And select a solid white desktop background, for perfect clarity. See edited OP for details.

P.S.: Issues #35 and #120 are not the same, but i guess they probably have some common roots... They are "twins"?

[SebastJava]

Obviously wrong shadow (OPEN IMAGE IN A NEW TAB, FULL SCREEN to see all the tiny details.)

And then it gets displayed correctly with a mouse hover, no mouse or keyboard clicks:

VM-SquaredShadows-02-2022-07-21_12.35.15.webm

mintUpdate: yes VM-inxi-2022-07-21.txt

[SebastJava]

@clefebvre I saw you changed the title. This "cropped shadow" issue is broader than that. It also happened on a Xed window and it was worst than with the session quit dialog. Check this update right here above: https://github.com/linuxmint/mint21-beta/issues/120#issuecomment-1191734508

[clefebvre]

I know. It doesn't need to encompass all cases. It's the same bug. Reproducing it 100% with one particular case is enough here.