You can use the spacebar on the song select screen to preview a chart using your current scroll options. However, some of them on my game (version 0.66.1) are desynced… and I have absolutely no idea why.
First off, I try to play with Xmods whenever I can, so I encountered this problem with an Xmod preview… but that apparently doesn’t matter, since even if I switch to a Cmod, the same desyncs show up.
Secondly, by “some”, I mean three (that I’ve noticed, at least), and my confusion stems from how unrelated they are. I ended up finding them by looking at MSD 0 charts, since that’s where I found the first of these.
At first, I thought that it was some negative BPM doing this, or the preview getting confused by stutters, due to the fact that these have off-sync previews:
…but the third desynced song completely destroys that logic, because the chart is a constant BPM with no BPM changes or stops at all (it’s a 6-key chart, but that’s probably irrelevant):
To make this even weirder, it’s only the preview doing this (the song and chart are synced just fine when you’re actually playing), and if I manually go back far enough into the preview, the sync fixes itself (until I leave and come back to it, of course).
Refreshing my file lists has changed nothing. Is this something other people can also observe, or should I be worried that I somehow have corruption in my files? I’d love to report this, but I can’t really do that when I don’t understand the problem that’s breaking the previews in the first place.