I am suddenly having the same problem.
Well, I tried this for about two hours and it didn’t work. I logged out, turned off my computer, went to Youth Orchestra concert to see my daughter’s boyfriend play viola, returned, tried again, and voila! It works. Thanks, WordPress!
This doesn’t work for me. It has been buggy since the beginning, I have upgraded WP a couple of times and even worse.
When I drag it to the right it looks ok and stays there, but when I save the menu it pops back over to the left and becomes a parent on the front page menu. Does anyone have a solution?