Sound/Menu Issue has me Stumped

Trying to write this out is weirdly complicated, but…

I’ve had the Samples for several weeks. Made loads of patterns and am having a blast.

But I made a new project, and now I have a problem. Any sample I add to any track, I can only hear the sample while I’m selecting it. As soon as I leave the Folder menu though, the sound disappears. It is still loaded on the track, but I cannot get any sound by playing the notes or playing the pattern. What am I missing?

Thanks in advance!

Some additional info: I was originally only adding new patterns under the STOCK project, on banks B-F. Once I created a new project, it basically copied everything on STOCK to my new project, 1_PRO. It seems I can no longer add any new patterns to the STOCK project, which was also copied to my previous new project which had the issue described above. But I did manage to create another new project that is completely blank and works as it should. Phew!

So I guess that’s good. But I’m still curious what I missed.