Leave note selected when adding palette items in note input mode

Note input mode generally assumes the selection will always be a single note, and things don't work as smoothly if this is ever not true. A particular case that came up in the forum is, adding a dynamic to a note leaves the dynamic selected, which might be useful in normal mode for manual adjustment but interferes with the operation of note input (tie button doesn't work, typing a note overwrites the one just entered, etc).

So I propose we disable the selection of the added element when in note input mode. PR forthcomng.