Highlighting inactive when page is opened with code editor active

This is a great plugin but I have one minor niggle. I have a page with a custom HTML block. In the page editor I switch to the Code editor, everything is highlighted, all is good. I save and quit the editor. If I come back to it later, the code editor is still active but I have not highlighting; I have to switch to the Visual editor then back to the code editor to bring back highlighting.

It may seem like a minor point but when you’re switching back and forth a lot it can become a little tedious.