[SOLVED] can't remove "Messages failed to send" bar

[chaserene]

Describe the bug

there is a room where I was trying to send a message while the server was unreachable. this generated a bar above the message composing box reading "Messages failed to send":

I tried to delete it with the trash can icon. it displayed the modal "Delete unsent messages," but choosing "Yes" didn't change anything.

I also tried the "Retry" button immediately after the accident, but it didn't send the message. I haven't retried it later because the message was no longer meaningful for the room.

I wanted to get rid of that bar without reinstalling the client. disabling some of the labs settings, including one that required re-downloading chats from the server (more on this below), solved my problem. it's unclear to me if it was the re-downloading that solved it, or the disabling of any of the labs settings. thanks for the helpful bug template though!

Additional context

• App version: 1.6.26.sc84
• Store: F-Droid official
• Related (?) labs settings: the following were enabled: Open at first unread, Mark chats unread, Enable swipe to reply in timeline, Enable threaded messages, Enable deferred DMs. I started disabling them in the same order. when I got to disabling threaded messages, the app restarted (which is normal, as the description below the setting noted) and re-downloaded my chats. after this, the bar was gone.
• Logs have been submitted using the app's built-in bug report (/"rageshake") mechanism: no

Upstream relevance

• Does this issue exist in Element Android? yes: Retry and trash can button do not work for failed (unsent) message deletion action element-hq/element-android#7815