just me feeling, but clicking on a folder to open it usually initiates a conversation with the mail server about if the folder is up to date or not and mostly initiates some updates.

So clicking the folder and right clicking might be a race condition where the folder is being updated. Where using the menu would see none of the update stuff occurring.

But this is not the support site for the add-on, so I am only guessing based on what I think I know. I that is not enough, perhaps try using the support link from the add-on home page which is given as https://github.com/thundernest/import-export-tools-ng/issues

Thank you. I had forgotten that "ImportExportTools NG" was an add-on. If updates are required for an IMAP folder, how long should that take? I tried it again ten minutes later, and had the same problem.

if you open the Activity manager, it should show which actions are active. I find my box spends a lot of time determining what mails to index in folders. But I have a Lot of email in some folders.

Hmmm. "Activity Manager". Never paid any attention to that, but yes, I can see how with IMAP that might be especially useful. I just moved over to IMAP from POP a year or so ago, and I'm still getting used to it.

I still do not "like" imap, but I am old school. My data not some possession of google or Yahoo or some other corporation, but it has it's uses.

I hear ya talkin'. I was a POP devotee until last year, and then, for an account that I need to access on several machines, IMAP seemed more appropriate. I still use POP for other accounts. Of course, for POP, archiving is trivial, but your collection of e-mails is then machine-specific.