voice cross line

on a piano part, Is there a way to draw a line indicating (for example) a voice movement from the end of the upper left hand voice to the beginning of the lower right hand voice ?

Dorico doesn’t have a general line-drawing option yet. You can fake it with a gliss line, since glissandos don’t play back either.

Indeed-- I fake it with gliss lines all the time since the text is easily hidden in the properties panel.