If you have more than a few projects, it can be nice to organize them with a structure.
This administration screen allows you to create some project groups.
The project selector will always have a last entry called All Projects which includes all projects, so you don't have to worry too much about forgetting one in the group selection.
The advanced button allows you to access the actual underlying JSON setting. This can be useful for example to create a copy of this setting for safe keeping.
In the following video (direct link here), see how to group projects together: