I think I found a bug. I won't look deeper into this as it is not important to me but i thought i can write it here so you know. or maybe it's even not a bug
When you have a scrollbar in the dropdown list of a combobox, neither the thumb nor the buttons seem to get a notice of a mouse hovering it. they are not drawn in hover state. however, in a multiline editbox and also in a listbox, they are drawn in hover state when the mouse hovers them.
this is with a custom skin, I didn't test it with taharezLook.