propagate_notification(NOTIFICATION_APPLICATION_FOCUS_OUT) causes data.blocked to be greater than 0, and finally the root window fails to add the ProgressDialog as a child node.

It seems that new child nodes cannot be added to the parent node during propagate_notification.

This is still not fixed and is available in Godot 4.1

The error is also present in v4.2-dev5

Also encountering this issue - frustrating

I have the same issue in v4.1.2.
Do you think this will be prioritized any time soon?

Disabling Save on Focus Lost is a workaround, of course you lose the ability to save on focus lost.

Disabling Save on Focus Lost is a workaround, of course you lose the ability to save on focus lost.

That's not a workaround, it's just a broken feature.

I have the same issue in v4.1.2.
Do you think this will be prioritized any time soon?

i don't think so unless some big shot on twitter or youtube spread it and its not really a big deal for some people so i dont think this will be fixed anytime soon

Disabling Save on Focus Lost is a workaround, of course you lose the ability to save on focus lost.

That's not a workaround, it's just a broken feature.

It works around the error, which automated testing would flag as an error.

It surely doesn't fix the cause.

propagate_notification(NOTIFICATION_APPLICATION_FOCUS_OUT) causes data.blocked to be greater than 0, and finally the root window fails to add the ProgressDialog as a child node.

The solution is likely to add a way to save all scenes/scripts in the editor without displaying a progress dialog, and use this when Save on Focus Loss is triggered.

Alternatively, we can get rid of the progress dialog when saving and move this to a non-blocking control displayed at the bottom of the editor (similar to a toast, though not the exact same). For instance, when saving a file, LibreOffice replaces its status bar at the bottom with a save progress bar:

I'd personally prefer this approach as I find the progress dialog on save distracting. We only need to keep it for operations that need to be blocking to avoid data inconsistency, such as resource importing.

This error is still occurring as of Godot v4.1.3-stable in the exact same manner, I agree with Calinou that a different way to show saving would be great, I also have found the dialog to be quite distracting but this error makes my output log ridiculously noisy over-time as I work on my project, I have had to disable Save on Focus Lost due to this issue as it has become frustrating to debug while this is occurring.

An option to temporarily hide internal editor errors during playtesting would be great so that my output is not cluttered by errors like this.

I've encountered the same issue in Godot 4.2.1 stable...

Also encountering this on EndeavourOS with Godot 4.2.1.
Thankfully this issue told me what's going on, as without a debug build of the editor you just get this error message without further detail:

ERROR: Task 'save' already exists.
   at: add_task (editor/progress_dialog.cpp:167)
WARNING: ObjectDB instances leaked at exit (run with --verbose for details).
     at: cleanup (core/object/object.cpp:2208)
ERROR: Resources still in use at exit (run with --verbose for details).
   at: clear (core/io/resource.cpp:493)
[1]    3340289 segmentation fault (core dumped)  ~/Tools/Godot_v4.2.1-stable_linux.x86_64 --editor

With the first two lines being repeated a lot. Would be helpful to either flag this as broken on linux with a warning on the settings or at least have more helpful error output. I was wondering for half an hour or so why my editor always crashed when I launched the game - turns out it's the save on focus loss instead of anything related to my code.

Any progress on this bug, it still available on version 4.2.1

Still an issue on 4.2.2 stable. While a fix would be appreciated, it should probably add to the log that the issue is from save on Focus Lost, that way we have less wasted time debugging code that is not relevant.