Yahoo Mail, Borders Shrunk. Help?

Upon opening Yahoo Mail today, the side borders had closed in toward the center. I didn't count the current line length but I'm guesstimating that it has shrunk from 80 to 60 characters long. I see nothing obvious to widen the text area.

Setup allows many changes but I don't see how to extend the text borders.

TIA :cry :major

 

Look if you can resize by clicking and dragging the border(s).
If not, post a screenshot.

 

SOLVED!

It solved itself this morning.

I don't like the self solving problems because I don't know how to repeat them.

Normally, when mousing across a sizable border, the cursor will change to a doubleheaded arrow. I didn't see anything like that happening.

Eldon, thanks for jumping in.