Alt Key-Up Event Not Being Sent to Application When Switching Workspaces

Distribution

Mint 21.3

Package version

6.0.4

Graphics hardware in use

NVIDIA GeForce RTX 4090

Frequency

Quite often

Bug description

I use the keyboard shortcuts Ctrl+Alt+Left and Ctrl+Alt+Right to switch between workspaces. It seems that if the keyboard shortcut to switch workspaces in a full screen application, when I switch back the application thinks that I am still holding down the alt key. I noticed this while playing games so I reported the issue to Steam's Proton team and they suspect that it is an issue with Cinnamon where the key up event is not being sent to the application after changing the workspace.

Steps to reproduce

1. Open a full screen application
2. Use keyboard shortcut Ctrl+Alt+Left or Ctrl+Alt+Right to switch to different workspace.
3. Use the keyboard shortcut to switch back to the original workspace with the fullscreen application.
4. Check to see if the application is still registering the Alt key as pressed.

Expected behavior

I expect that applications would only detect me holding down the alt key if I am actually holding it down.

Additional information

Here is the related Proton issue that I had opened: https://github.com/ValveSoftware/Proton/issues/8120#issuecomment-2374512572

No files or tests are named in the report. Start by reproducing the workspace switch with a fullscreen application using Ctrl+Alt+Left or Ctrl+Alt+Right, then trace Cinnamon's workspace-switching and keyboard event handling. Done means the application no longer observes Alt as pressed after returning to its workspace unless the key is actually held.