Need Help with UI - Scene/Object Browser

 From:  sneather
5319.1 
Hi:

I was just sent a detailed CAD .STEP file by a client. It has hundreds of parts, with (seemingly) long names.
However, unlike almost any other current design program, I can't seem to click and drag to change the size of the browser windows. "Squishy UI" I think it's called?
All I can find in the Options menu is the choice to move its location. But nothing helps me adjust the width of those browser windows.

Please tell me I'm just missing something...

Thanks.

P.S. This is for the Mac version.