It’s currently quite difficult to locate scrollbars, particularly at lower screen brightness and I think they would be much easier to see if either the bar or the background was made lighter than the overall window colour.
I’m attaching some mock-ups for reference 
Current example:
Lighter scrollbar:
Lighter scrollbar background:
The problem is the scrollbar color is linked to the background color (gtk_background), and the selected scrollbar handle is linked to the darkest background color (gtk_darkest). So, unless something is changed in the Ardour’s code, for very dark themes this problem is impossible to fix.
Well ardour has its own gtk fork now so I dare say nothing is impossible
I meant that with Ardour’s current theming capabilities alone is not possible to fix this problem.
What part of my sentence you didn’t read? 
Fair point, I read to fast !
