How to fix TreeView in Atom?

Question

atom

One day I turned on the atom, but my dear socket with the project is gone. Well, it doesn't matter, I opened it (although I still have no idea what happened), but every time I restart Atom, this panel is hidden. I launch Atom by opening a file, and always the panel was open, and the project tree was displayed in it. I don’t know what happened, and how to fix it too.