Dialog windows created by LrDialogs.presentModalDialog() don't always close fully on exit.
To reproduce on LR 14.2 / Mac OS 15.3.2 / Macbook Pro 16" 2023 Apple M2 Max:
1. Download and install this plugin:
https://www.dropbox.com/scl/fi/rpm9osljz9yv9arxu8yqk/dialog-bug.lrdevplugin.2025-03-24.zip?rlkey=fuv...
2. Do File > Plug-in Extras > _Dialog Bug > Bug and observe this dialog:


3. Click OK and observe the dialog close properly.
4. Do File > Plug-in Extras > _Dialog Bug > Bug again and observe the same dialog.
5. Click OK and observe that the dialog hasn't completely closed:


6. The dialog remains until you restart LR.
* * *
This bug persists after resetting preferences and opening a new catalog. I first noticed it with my Debugging Toolkit, where it's a serious annoyance. Nine others have reported similar symptoms with creating snapshots starting with LR 14.1.1.