How to show a Docked window's scrollbar?

I'm trying to get a docked window to simply show scroll bars when contents are clipped on client resize like how the main window does.

I've been looking for components with a jscrollpane to use. It gets complicated when I try to use a template repeater/canvas for the scroll pane as I am also trying to use a template repeater within. It may be possible but I wouldn't want to resort to trying to pass datasets through the nested repeaters and I would like to keep using template repeaters inside.

More context is that this is for a docked navigation menu where I repeat navigation buttons with template repeaters.

Is there any other component with a jscrollpane that I am missing? I'm guessing we won't be having that container in vision any time soon.