When opening the menu on a particular message in a ticket, it doesn't seem to be possible to close it when you tap anywhere else on the screen, appart from tapping in the exact same place you tapped to open it. This is not constant with the menu at the very top of the ticket, which does correctly close if you tap outside of the menu.
As a result of this bug, it is possible to open both menus at the same time as shown in the below image.