beat mode single7 displays in center always, even with center 1 player disabled

When playing single7 style in the beat game mode, the playing field appears in the center even when playing with center 1 player (solo single) off. The life bar and score and such will appear on the left hand side (or right) if I'm playing with center 1 player off, and in the center if I'm playing with center 1 player on as expected, but the play field will always appear in the center. This isn't the case with single5 however - if I play a 5-key song then the play field will appear on the left or right as expected.
I think this has been done some time between stepmania 5 beta 4 and 5.0.5, because I gave a friend of mine some BMSes to try with stepmania 5 and he was using beta 4. The play field appeared on the left hand side as expected.
Is this a bug or was it intentional? Was it a source mod or is it somewhere in the theme? I can seem to be able to move around the play field in any game mode but beat single7, which is especially noticeable in Tony's beatmania IIDX 15 theme, where the playing field appears not where it should be but in the middle of the screen.

This occurs because the field is wider than half the screen, so the engine decides it's too big to fit in the normal area and puts it in the center.
I can explain more later, but basically for 5.0.5 and later there's a system that allows a theme to specify how large the margins on each side of the field should be, and it's placed centered in the area given. If it doesn't fit, it's centered on the screen.

Cheers for your response. I did find something about margins in the metrics for the fallback theme and was fiddling around with that, but it didn't produce any effect. It shouldn't really matter if I change it to appear back on the player side because Stepmania doesn't seem to allow versus play for beatmania mode in the same way as in dance mode (requiring special 2-player charts, rather than each player playing the single chart). Just a quick question, will I have to edit the source code to allow the playing field to appear as it used to?

Post a link to the theme and I'll fool around with it. I wrote the change to how notefields are positioned, so I know what's going on inside.
Worst case, I can put in a cheap hack in the theme's ScreenGameplay lua to reposition the notefields.

Im also experiencing the same issue with this theme.

Here is a link: https://sites.google.com/site/tony8642005/themes/iidx15-troopers

Everything besides the field centering is perfect with 5.0.8. So stoked to finally have playable iidx on a mac if this is an easy fix..

This is a dreadfully hacky fix, but it might just work for you -
make a file called "margins.lua" in the Scripts folder of your theme and paste this in:

function GameplayMargins(enabled_players, styletype)

	return 1, 1, 1;

end

That's actually exactly what themes are supposed to do to position the notefield now.
The first value is the space from the left screen edge to the edge of the left notefield.
The second value is the space between notefields in 2 player mode.
The third value is the space from the edge of the right notefield to the right screen edge.

Thanks for the reply guys! That worked great with a -143 adjustment in the first value. Thanks so much!