Mail Window Size (compose or reply) way too BIG

I had tried deleting the Mail preferences files, and this did not solve the problem. Also tried deleting the signatures multiple times, to no avail.

However, last night I stumbled on a solution (one thread tipped me off) that is bizarre, and a strange glitch. If I opened a new message (compose new message) window via the keyboard command, rather than the tool bar icon, and resize the window to the size I want by default, that size sticks (even after quitting and restarting mail). And it seems to have also affected the default size when I use the tool bar icon from that point on. So an odd thing: if one uses the keyboard command to open a new message window (or via the "file" menu command), and sizes it as one wants, that then becomes the default window size. I think the reason my problem arose in the first place was that I'd done the same thing before (used the keyboard command to open a new message window) and sized the window as full screen by accident, and that became my default window size -- I couldn't undo it until now (when I finally discovered the fix).

Bizarre... but so far so good. Crossing fingers. Thank you both for your help.

Thanks, Becky. I hope my discovery is helpful to anyone else who has had this problem. I'd not seen this "fix" (which I believe was also the inadvertent cause of the issue in the first place... using the keyboard command or the "file" menu command to open a new/ compose message window, then resizing that window, sets that size as the default for future new windows) anywhere else. Hope it helps others.

Dan