How do I make the "Manage Attachments" window open full-size by default?

[Marcel Lee]

When you click the "Manage Attachments" button, the window for it only opens partially. You have to click that little square on your upper right to make it full-size.

How do I make it open full-size by default?

[Dismounted]

It should open full size. Atleast that's what mine does.