I'm using command line MAME 125u4 but I launch the .exe in windows. When the game list pops up in DOS, some of the games are highlighted with a gray box...what does this mean?
I can't tell any status differences between those with and without the gray box and they both seem to play fine.
DOS is often confused with command-line - the program is still running in Windows, just in a command box.
Err, nitpicking, but that list the OP mentioned is popping in as windows graphics, and has nothing to do with either DOS or commandline.
I'd say:
"DOS is often confused with command-line - mame is still running in Windows, just
starting from a command box, and runs in a normal windows window (or full screen depending on settings), with a default font that looks DOS-like."
The default font, IMO, is arcade-like, and the dos font was arcade-like too, but that's too nitpickety even for me.

Anyway, the default font can be changed, and to
a more windows-like font if you want.
Anyway, the gray highlighted game name lets the user know that the set is not a parent set. The built-in minimalist gui for MAME only accesses sets for which you have a .ZIP container showing in your rompath.
What he said.
