dunno , I have 3 monitors and have it at 1680x1050 on the one ( windowed mode ) works fine.

drivers up to date?

In my case, the 1024 x 768 window (on a 1440 x 900 desktop) occurs when you set the windowed mode from the game program's inner options.

The solution is to edit the user.setting text-file with Notepad (NOT Wordpad or Word).

1. Find that file in your IrocladGames\SinsofaSolarEmpire\Setting folder.
2. Right-click on the user.setting file, and select open with Notepad.
3. Find this group of lines (the numbers are an example for my original situation) :

VideoIsWindowed TRUE
VideoRefreshRate 60
VideoFullScreenWidth 1440
VideoFullScreenHeight 900
VideoWindowedWidth 1024
VideoWindowedHeight 768

I changed the Window Width line to 1360, so now, I have a big 1360 x 768 window on a 1440 x 768 desktop, on a 17-inch widescreen (which required me to keep the 768 part).

Unfortunately, at the moment, you cannot do that from inside the game program, which will impose, as you have said, a too small window. You have to do it yourself by editing that user.setting text-file.

When set to windowed mode the game opens at 1024x768, all you need to do is maximize it like any other window (you can freely resize it while it's running).

It is one of Microsoft's "Games for Windows" requirements that we store all user-generated application data in this directory.