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:
Mellann (Red Fraction Pack)
The Device Has Been Modified (Community Keyboard Megapack Vol. 4)
…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):
Kingdom of Silence (Stepping Stones 4, any difficulty)
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.