Windows 7: WLM

Hi,I'm using windows live mail due to Windows 7 upgrade,All working well when I select the F5 key pad to check for any mail the big box opens up is there any way of keeping that to a small box.I click on the details tab to close the large box to the small one.is there a method of keeping that box a small one.
Thanks.

When I tried it the Window opened fairly large but not "maximized". That means the size can be adjusted to whatever you want using the mouse to drag the lower right corner. The keyboard shortcut merely opens the program to the size you last left it at.