Vim: How can I disable the mouse in Operator-Pending Mode?
Solution 1:
:help 'mouse' won't help, here, so you can set it to a or any desired value.
You could disable the left mouse in operator-pending mode, though:
onoremap <LeftMouse> <Nop>
which prevents mouse clicks motions in operator-pending mode. Note that, with that mapping, a mouse click is not considered as a motion anymore but it also sort of "breaks out" of operator-pending mode, which may or may not be a problem.