fix #62961: multiple hairpins added on list selection

[MarcSabatella]

Turns out it isn't straightforeard to just add a single hairpin to each note. cmdAddHairpin tries to find appropriate notes within the selection; it isn't actually passed the current note. We could add that as a parameter, but then it still wouldn't be clear when to use the current method and when to use the passed note. It might be nice to support a single note selected on each staff, but since we support ranges across staves, that should be good enough most of the time.

[lasconic]

mm this is a pity. If I'm not wrong, it means that selecting a note and another note further on the same staff and pressing the crescendo shortcut will not work anymore.

[lasconic]

I tried a couple of other things like clearing the selection or removing cr1 from the selection but it's not really good. We lack the information that it's a call made several time.
Another solution could be to disallow the addition of a hairpin at the same tick/tick2 and track. In most case, it means the two hairpins are on top of each other anyway. Sibelius does allow this but draw the second hairpin in red. (the third one hide it though..)
Last solution, we could differentiate a single call from the shortcut, from a (potentially multiple) call from drag.

[lasconic]

I merge this for now.

[MarcSabatella]

FWIW, it didn't really work correctly to select two notes then apply the hairpin - it triggered the bug being fixed here. That is, you got two overlapping hairpins.

I'm sure it would be possible to fix this better with a more substantive change to how the code is structured. I thought about changing the code upstream where we loop through the notes applying the drop. We do already special case slurs and hairpins for range selections to prevent exactly this problem - we only apply to one note one each staff. We could do something similar here, and then also make sure Note::drop() passes in "this" so cmdAddHairpin knows what is being applied to.

[lasconic]

It was working to select two notes and use the shortcut since the cmdAddHairpin function is called only once.

[MarcSabatella]

Yes, true.