Board Thread:Support Requests - Getting Started/@comment-28408407-20190525113435/@comment-26569706-20190525131418

This is a rare problem that I encounter every so often (maybe every few weeks) in the visual editor. I don't know why that happens.

Try refreshing the page a few times. If that doesn't work, then just take a break from editing for a few hours. It should work when you come back.