H'mm on this build I've just noticed search (bottom left hand corner) is not working and won't let me type anything ...windows search is running in services.
I also had this issue... It worked after disabling Windows Search service :\ Try with it Disabled and then turn it on back again and see if it works. Maybe a restart to the service also solves this issue but didn't check when I noticed the problem which is now gone with and without Windows Search service on
Problem is users simply wanted tabbed file explorer and command prompts and MS in typical convoluted fashion over complicated things by trying to tab the whole world.