Excellent, @GoToLoop! Thanks for the thorough explanation.
I tested this out, and can confirm that fixing the GitHub slider example requires the few adjustments/additions you mentioned – specifically:
class SimpleSlider(ActiveElement):
...
#def mouseDragged(self, mx, my, dx, dy ):
def mouseDragged(self, *args):
mx = args[0]
...
def setup():
size( 200, 220 )
Interactive.manager = None
#Interactive.make(this, True)
Interactive.make(this)
...