Atom 1.0.0, running on Yosemite.
Tree View will not allow you to add a project folder if the folder name begins with a dot.
Core package Tree-view’s “Hide Ignored Names” is NOT checked.
OS is set to show hidden folders in Finder, and will show those starting with a dot.
Treeview will show dot folders under the root of a project folder, but they don’t get displayed in the “Add Project Folder” dialog, so there’s no way to select them.
Example: “/Users/myUser/mySubFolder1/.myDotFolder” does not get displayed in the “Add Project Folder” dialog.
However, if “/Users/myUser/mySubFolder1” is selected as a project folder, then “.myDotFolder” will show up under it in the tree view.