How do I enlarge the too (right hand) pane in adobe acrobat DC?

I want to make the tool(right hand) pane bigger so I can see form filed names but I can't seem to find a way to do this. I can see a way to make the left hand pane bigger by holding the cursor on the right hand edge of the pane till I get the double bar with the arrows attached symbol, at which point I can drag the edge of the tool pane and make it larger. However, that option does nor seem to be availabe for the tool (right hand) pane.

Can I adjust the size of the tool (right hand) pane nad if so how do I do it? I can't see to find anything on this in the forums or on the internet

Kind regards

Robert Smith