AltTab shortcuts stop working after hiding a window from AltTab

[alt-tab-macos-bot]

This issue was opened by a bot after a user submitted feedback through the in-app form.

Message:

Unable to show a window again.

Steps to reproduce:

• Click on the desktop
• Click on the window
• Invoke AltTab
• Put the focus on the window
• Hide the window
• Try to show the window

It seems that all non-global shortcuts become non-working.

[lwouis]

I couldn't understand the steps. How was the window hidden? Through AltTab or through macOS built-in app-hiding functionality? You can't hide a window; only a whole app (= all its windows).

[decodism]

I sent this feedback.

Clarification: the last three steps are done in one go in AltTab. By "put the focus on", I just meant "select". Hiding is done with the keyboard shortcut.

I hope you can reproduce it now. (I'm on Big Sur.)

[decodism]

I found a dirty fix: add App.shared.activate(ignoringOtherApps: true) in the "applicationHiddenOrShown" function.

[lwouis]

Thank you for the clarifications @decodism! I was able to reproduce the issue!

I think it can be summed up as such: you can't hide then show an app, if after you hide it, the new active app has no visible window.

Your use-case is with the Finder app, but I could reproduce with any app.

• Finder open, no window. Chrome open, 1 window -> If I hide/show the Chrome window, it fails at showing
• Finder open, 1 window. Chrome open, 1 window -> If I hide/show the Chrome window, it works fine

Also interesting to note, if you close AltTab UI and reopens it, then there is no issue. Also, when the issue happens and the shortcut to show the window does nothing, you can't close AltTab UI with the normal alt-escape shortcut.

Looking at logs, it seems that the show order is not sent in that scenario for some reason.

[lwouis]

Ok I think the issue is that AltTab somehow loses keyboard focus in that scenario. Thus the Show shortcut or the close UI shortcut not working.

[lwouis]

This was a logic bug in the applicationActivated function. I wrote a fix.

Very interestingly, testing the fix, I found that in a particular scenario, if I spam the hide/show shortcut and the tab shortcut at the same time, I eventually get the app in a bad state. It repeats the tab shortcut without me holding it. It also ignores local shortcuts. This issue could be related to #719

It's hard to reproduce as you have to spam keys quite a lot. I captured the issue on video, but in that particular reproduction, the tab key doesn't repeat on its own. It's only local shortcuts that stop working at the end of the video

Update: I captured the tab key repeating (in addition to the local shortcuts not working) in this video.