Is there a way to theme the scrollbar for GtkScrolledWindow to be outside of the frame border?

I’m updating the Clearlooks GTK2 theme for GTK3 (Clearlooks-Phenix) to fix bugs which have occurred since its initial release.

One of the changes I’ve noticed between the original theme and the GTK3 one is that scrollbars for scrolledview widgets are now contained within the frame border.

Is there a way to modify these widgets to draw the scrollbar on the outside of the frame to reproduce the original design?

Here is an example of Pluma in its current form:

image

I would like to shrink the frame to border only the content with the scrollbar resting on the outside.

Can this be done?

See this mockup of how it used to look (how I want it to look) in GTK2:

image