How to show all folders under Documents?

[johnaweiss]

I only see the folders that fit on the screen. How to reveal the remaining folders?

[johnaweiss]

Or, how to reduce the Documents column-width? It's much too wide.
Edit: I found it in Menu Look > Sub-menu width. Much better:

[johnaweiss]

But even tho i could shrink column width, i still can't figure out how reveal anything beyond what's visible using just the mouse. Is there a way?