[quote user="Bob"]However, when I open up a new message window I have to click on the "maximize" button to get that window to fill the screen properly.[/quote]

It's always been like this, the workaround I use is to "pseudo-maximize" the inner Pegasus Mail windows by opening one by one as a single window and select Window => Tile from Pegasus Mail's main menu bar for each of them: This kind of "maximized" Window will be restored properly the only disadvantage being the additional title bar at the top.

In Tools|Options|Message Reader  the box is checked on "Always save the lasr window size and position used". 

However, when I open up a new message window I have to click on the "maximize" button to get that window to fill the screen properly. If I don't, I have 2 scroll bars on the right (one of the scroll bars disappears when the window is maximized).  In addition, when I go to the attachment tab, the "Recently used files" and Add Attachment" buttons are out of view.

I'm using Windows 7 now, but it also happened in Windows XP.

Any ideas on why this might be happening?