Alt + Tab + ~ can sometimes blank out the top bar

[Colonial-Dev]

This is a really weird bug, but after some testing I'm pretty sure it's caused by this extension.

Basically, if you press Alt + Tab + ~ repeatedly (which is easy to do accidentally, at least with my keyboard) the top bar/activities bar will eventually "blank out."

Its black background still takes up space on the screen, and you can interact with its contents if you know where to put your mouse, but any icons and text will vanish. Pressing the same key combo a few more times brings it back.

I'm guessing this is some sort of weird race condition, because the bar also gets blanked out when in coverflow mode.

Other notes:

• Disabling the extension does not unblank the bar.
• Disabling the extension does prevent the issue from occurring.
• So far, I haven't been able to replicate it with any button besides ~. I'm unsure if this is because tilde is actually special, or if I'm just not finessing the alternate buttons correctly.
• I would not consider this a huge deal; I'm mainly filing this issue so other people can know they aren't tripping.

[YuanchenZhu2020]

I came out the same issue on Fedora 37 when I switch to wayland.

When I press Alt + Tab, you don't see any animation, but you can switch Windows. After doing it two or three times, my top bar will be transparent. I can see the background and can also interact with it, but the black background, icons, texts, everything is become transparent.

[p91paul]

I reproduced this on Gnome 43 on debian. I fear current master declares Gnome 43 as compatible, but it's not. I reverted to version 55 on extension.gnome.org (a later version is probably fine but I didn't try them all). To me, it just happens the first time I trigger the extension with alt+tab, no need to use ~ or do it multiple times.

I'm getting this log:

giu 17 16:15:07 paolo-desktop gnome-shell[13818]: [0x55cab0bf8dd0 MetaWindowActorWayland]
giu 17 16:15:07 paolo-desktop gnome-shell[13818]: [object instance wrapper GIName:Meta.ShapedTexture jsobj@0x34a173961d80 native@0x55caadfbe420]
giu 17 16:15:07 paolo-desktop gnome-shell[13818]: [0x55cab0bf8350 MetaWindowActorWayland]
giu 17 16:15:07 paolo-desktop gnome-shell[13818]: [object instance wrapper GIName:Meta.ShapedTexture jsobj@0x1feecb2d6d80 native@0x55caaeff6110]
giu 17 16:15:07 paolo-desktop gnome-shell[13818]: [0x55caaf209d30 MetaWindowActorX11]
giu 17 16:15:07 paolo-desktop gnome-shell[13818]: 
giu 17 16:15:07 paolo-desktop gnome-shell[13818]: JS ERROR: TypeError: texture is null
                                                  _createPreviews@/home/paolo/.local/share/gnome-shell/extensions/[email protected]/coverflowSwitcher.js:70:21
                                                  show@/home/paolo/.local/share/gnome-shell/extensions/[email protected]/switcher.js:172:14

The last line is the error, the previous ones are me logging the compositor and texture variables on line 70. As you can see, when running on wailand, the compositor variable can be either MetaWindowActorWayland or MetaWindowActorX11. The latter probably does not have a "texture". I'm probably using an X11 application on Wayland, but I don't know which one it is.

The last change in that area is 9abe7ed, which likely broke Gnome 43 on wayland. @dsheeler you should remove 43 from metadata.json, and release a new version for Gnome 44 only (provided it works on Gnome 44, but it probably does if you are running it), then unrelease from e.g.o. all versions containing that commit and declaring Gnome 43 compatibility.

[dsheeler]

@p91paul Thanks! I don't typically run wayland... will have to start testing deliberately

[dsheeler]

@p91paul, can you somehow test on 44? It works for me

[dsheeler]

@p91paul, I was able to test under 43 and have errors, but on 44 it works. So I'll do what you suggest with respect to releases/unreleses. Thank you!

[hajosc]

Thanks so much, both! I'm on 43 with Wayland and indeed, after uninstall and reinstall via extension.gnome.org my favorite switcher is back again! I guess the issue can be closed...