Two clicks before note enters

Does anybody recognise this behaviour and is it intentional? When I enter notes by clicking, usually the first click places the note where I want, but sometimes, especially if I change the note value, I kind of need two clicks before anything happens. The light blue rectangle is there, the ghost note head is there, but first click doesn't place anything there. A second click (without moving the mouse cursor) places the note there. It's very annoying, because I haven't figured out what causes this, what do I do differently when it needs two clicks and when it needs only one click. I have this vague feeling that this is intentional behaviour, it's like the first click places the focus or cursor or something in the right place (a bit like when you activate an underlying window in Windows) although I can't see anything that has got out of focus and returns with the first click.

Windows 10 and MuseScore 2.1.0