Corkboard not working

I am beyond frustrated trying to fix this. It’s been working fine for years and now, for some reason Draft doesn’t have a drop down arrow next to it. So when I click on it all my cards don’t come up on the Corkboard or in the Outline either. What is going on? It used to be I could click on Draft to make all the nested folders open or close. Please HELP!

I’ve finally figured it out. Somehow all my chapter folders had become top level alongside Draft instead of nested under Draft. That has just done my head in…