1) if oneshot=True the pf.canvas.selection_accepted is always True, even if you ESC

2) the first time you pick the ESC does not work. You need at least to left click before.

3) sometimes, the very first time you select with a rectangle you get:
 Traceback (most recent call last):
  File "/home/gianluca/programs/pyformex/pyformex/gui/viewport.py", line 1340, in mouseMoveEvent
   
func(e.x(), self.height()-e.y(), MOVE)
  File "/home/gianluca/programs/pyformex/pyformex/gui/viewport.py", line 1253, in mouse_pick
   
self.draw_state_rect(*self.state)
AttributeError
:
'QtCanvas' object has no attribute 'state'