Dears,
Lately noticed that the slider control is missing some properties in the GUI Editor (lines #36 to 41 in PG) below:
Unless I missed something, you cannot set the thumbColor (independantly).
Unless I missed something, when you clamp a circular thumb the bar gets a cornerRadius.
Means it must be implemented somehow. But I don’t know how to access the ‘bar’ to add a corner radius. And anyway, if it’s possible to display the bar with rounded corners when clamped and circular, I’d also like to have this option of rounded corner bar added when not clamped/not circular 
Thanks for considering my request/suggestion and meanwhile, have a great day 