I'm not sure if this is just at certain breakpoints or if something isn't loading, but on https://next.www.documentcloud.org/projects/ if I hade the sidebars, I don't get the "bring back sidebars" button. Had this happen at 1250 pixel width and the simulator as shown. Doesn't seem to be consistent for me.
There should be buttons on the left and right side to show the sidebars.
Feedback from @morisy:
There should be buttons on the left and right side to show the sidebars.
In this project layout, we should have similar code to the DocumentBrowser.