I found a potential issue and kindly ask that you try to reproduce what you observed using this internal test version:
Thank you very much! That did the trick.
Dave
With this test version I do not get any message boxes any more, just an indicator in the status bar.
Excellent — thanks for testing this version and confirming the fix!
Do you have
Options → Messages → at unsaved changes enabled and
Options → Tags → Save tags when using arrow-keys/single mouse click disabled?
Yes
no, that is enabled (as shown in the screenshots earlier in this thread)
I got message boxes with these settings in the non-test version.
You only get the message if you disable auto-saving of changes.
From the docs
at unsaved changes
If enabled and auto-saving changes is disabled, shows a confirmation message that allows for saving any unsaved changes made via the Tag Panel.
The confirmation message is shown to prevent accidental loss of input and is not needed in case auto-saving is enabled.
This is most likely another indicator that something was wrong in this area.
OK, I set "after save" to create messages and the behaviour I tried to provoke is not there any more.
So everything seems to be fine now.
Just a small addition regarding how easy this issue was to reproduce: I'm sure that you could reproduce it every time you've tried, because your installation, with your Windows version and state of updates, triggered exactly the bug you've described.
Others who've tried to help weren't able to reproduce, because the behaviour depended heavily on the specific sequence of Windows messages the header control and the list control were sending. This seems to differ from Windows 10 to Windows 11, and parts of the code involved also differ between v3.31 and the latest beta version v3.31f.
I just wanted to add this note because I feel that it's often not so straightforward, and I wanted to make sure you know that nobody was ignoring the steps you outlined to reproduce the issue.