[Squeak Projects] previousProject vs. nextProject ... need lastProject?

Looking at the world menu, I always thought that "previous project" means "the one I just came from:

However, looking at the enter-code in Project, the variable "previousProject" has a counterpart "nextProject", which both establish a linear navigation history:

Consequently, repeated selections of "enter previous project" will not cycle between two projects. Instead, clicking on "previous project" is more like "enter parent project" ... at least for my usage behavior.

Then again, Etoys has this nice navigation bar, where a linear navigation history makes sense:

I am confused. :-) Is there an entry in the world menu missing? Or should we save "lastProject" in Project to go back and forth between two projects?

Best,

Marcel