I find selecting multiple messages very hard.
I single-click the first message, then single-click the others while Shift is held. That way, I can drag multiple messages into another folder.
I find this works, but more often than not, RC misinterprets the single-click as a double-click and opens the selected message in a new tab. This is not only annoying, but also raises my concern as this might mean to open spam messages.
Is multi-select not working very well, or am I doing it in the wrong way?