Add a test of multiple project browsers on a page

Holy shit -- in cursory manual testing, I confirmed that everything in the testing punch list, works. Hot damn.

So all we gotta do is a write the test here, but it doesn't look like we are going to have any bugs to deal with.

This looks great. The changes to main.js are so clean!

Merged !751 🎉

Automatically closed - issue fixed for 2 weeks with no activity.