Arrowhead bug

Hi,
I don´t use this command too much (arrowhead on curve), but does it work on mac? I can´t make it work!

Using Version 6 (6.23.20035.13182, 2020-02-04)

yeh works ok here on Rhino6 Mac & WIP Mac

weird, WIP works fine here as well, R6 not.

Works for me too in latest version of Rhino 6!

Hello - what happens? Does the command start then do nothing when you click on a curve, or?

-Pascal