I found this article:
Replace a Window's Internal Scrollbar with a customdraw scrollbar Control
https://www.codeproject.com/Articles/14 ... ormal&fr=1
Can this method of customizing a scroll bar be achieved by AutoHotkey?
how to custom draw a scrollbar??
Re: how to custom draw a scrollbar??
If the C++ script works, then I imagine it could be done through translation. You could try it. An aid to the translation is the similarity in syntax, probably even moreso with AHK v2.