Span a volta over several measures with the mouse

Hi!

I wanted to extend my prima volta over several measures.
After trying hopelessly during half an hour with the mouse/inspector, I gave up and searched for the web and got the answer (shift-left/right).
http://musescore.org/en/handbook/volta

My question is: while the technique with the keys shift-left/right is perfectly ergonomic, it's not particularly intuitive (my opinion! :-) )!
Is there a way to do it with the mouse? For example, it could be possible to be able to do it by moving the red-dot (anchor).

Thanks.