Shortcut (Ctrl+[, Ctrl+]) for back and forth in the history navigation have disappeared

I have an old version of the Workflowy here where this Easter egg like shortcut is still working, but in the last version, it's not working anymore.

Pressing Ctrl+[ it works very similarly to a back button on a browser. It navigates through your history navigation, not your item hierarchy. 

I know it's not documented on the shortcut help panel, but I've discovered it by accident and it's being very, very useful to me to do a lot of exploration and navigation tasks.