Why do some of my top-level projects have tasks and others don't?
I'd like to create "top-level" projects that are collections of projects and as such don't have any tasks. Clicking on such would reveal the list of projects within them rather than tasks.
Got it figured out. Adding an asterisk in front of the project name turns it into a project folder. That's exactly what I wanted to do. Great product, Todoist!
please note that you can also indent projects just as you do with sub-tasks. To do so, please use the gear icon visible when hovering over a project name (on the project list at the left side) and choose "Edit name".
You will then be able to use either the small arrow buttons to indent the project making it a sub-project or press and hold the Ctrl button and then use the Left/RightArrow keys.