Create-a-Style Glitch?

[ZapKid]

I was building a gorgeous modern house, but at one point, I tried to use create-a-style and the create-a-style window that has all the information disappeared. I tried clicking around (It was sort of like pressing tab except being able to move around to, and the tabs at the bottom left with the floor stuff were open, except the building stuff was gone). Eventually, I just had to quit because I couldn't do anything, and I lost the house 
Does anyone know what happened? (I have no mods/cc.)

[loveSims]

I don't know if this will help but do you  sometimes clear the package folders in your thumbnails folder? I build 3 small clubs and see that it get quite big. It is safe to delete, I delete mine about every month.

[ZapKid]

I don't know if this will help but do you  sometimes clear the package folders in your thumbnails folder? I build 3 small clubs and see that it get quite big. It is safe to delete, I delete mine about every month.

Ok, I'll try that. Thank you