Show popup in context when multiple messages are selected

Hello,
Since the last update, I can only move one mail after one.
I was used to select several mails and moved them with quickmove. But now, when I select several mails the "Quick Move" button disappear and the shortcut has no effect.
Thomas

Start by reproducing the issue in Thunderbird with several messages selected, checking both the Quick Move button and its shortcut. Trace the selection handling and popup/context behavior in the add-on, then verify that moving multiple selected messages works through both entry points.

Written by the indexing model from the issue text.