I'm gonna go look this up, but on the off chance anyone has a second, why can't I get the screen size to stay set to 16:9 in Mame 115? Every time I set it, it goes back to 4:3.
AH, let me guess - Widescreen is not supported in Mame v.115 maybe? Just a guess - seems a bit unlikely as it was in previous versions, but as I know often one thing is changed / dropped to improve another.
When you say "widescreen", what do you mean? I think you're using it the opposite of how mame views it.
Currently, Mame looks at the desktop resolution, and guesses "this is widescreen monitor" or not. If it decides it is widescreen, mame adds the black bars to keep the game 4:3 (the original machine's monitor resolution). I think it's been this way since 0.106, or there abouts.
In the past, mame relied on the user to tell mame if the computer screen was wide or not, and if it was told your screen was wide, then it did the same as above. This started a
long time ago, around 0.53, so I'm not sure if this is what you mean.
If you want the image to take up the whole screen, you have to lie to mame and tell it that your screen is 4:3 ("aspect 4:3" in mame.ini). This option used to be called screen_aspect.