First response after a quick try:
I have 1 folder setup as a monitored Inbox folder.
When I deleted files from that folder through MS Explorer, and then restart MB, the new functionality seems to work well, and the Inbox count is correct again after confirming deletion from Library.
But when I deleted those tracks through MS Explorer, and then perform a file rescan of the concerning folder through the computer browser in the left panel, the track count at the Inbox is not updated. (it is updated correctly though at the status bar at the bottom of the main panel)
So:
1. could Inbox track count please also be updated after a rescan?
2. could you create the option to right-click on the Inbox, performing 'rescan Inbox'?
edit:
I do experience one small problem, which is that after restarts, MB keeps asking to remove a specific file which I already confirmed to be deleted from library.
When I can give more specific info on when/why that could be happening I 'll re-report.