Move to archive button is there, but not always clickable


I have seen similar conversations about this feature, but none exactly match what I am experiencing, so starting a new conversation…

I am using eM Client version 7.2.34711.0 on macOS Mojave 10.14.3 (18D109).

My client has two IMAP accounts setup (call them A and B), pulling from two different mail servers.

When I view Inbox A directly (under the account, Inbox), the Move to Archive button is visible and functions as expected.

When I view Inbox B directly, the Move to Archive button is NOT visible.

And when I view All Inboxes (under Smart Folders), the Move to Archive button is always in the toolbar, but if I am reading an email from account A it is active, and if I am reading an email from account B, it is inactive.

Comparing the two Accounts screens shows no difference, aside from Host, Port, etc.

Any idea what else could cause this variance?

(Additional frustration: To keep my Inbox clean, I “manually archive” account B (dragging emails into that account’s my Archive folder).  But this action somehow is not included in the Undo stack (Ctrl+Z undoes the _previous_ event, not the manual archiving…)

Thanks a lot,

Some providers like GMail, provide the Archive feature, while vanilla IMAP servers probably don’t. That is one reason I can think of why the button is not there for Inbox B, and why it is disabled for messages on that server when viewed in the Smart Folder.