select
In 'Set/Replace' mode this is not a problem, but 'Extend' or 'Subtract'
modes were useless with the current behavior.
The problem here is that 'node.select' fires before 'node.select_box'
(which is fine) but deselects immediately on click.
This issue has come up before in other editors, see
{T70457}
{rB395dfff103e1}
{rBa8ea1ea1b7d5}
Now delay deselection in empty space to mouse release (same as done in
before mentioned report).
also related:
ref T57918
ref T63994
Maniphest Task: T86867
Differential Revision: https://developer.blender.org/D10801
926f7612fd