The reason the Visual Editor won't work with an HTML5 DOCTYPE is because it was built around HTML 4.01. As a result, it does not recognize HTML5 tags such as <video>, <audio>, etc. If you must use the Visual Editor, enter a different DOCTYPE.
The reason the Visual Editor won't work with an HTML5 DOCTYPE is because it was built around HTML 4.01. As a result, it does not recognize HTML5 tags such as <video>, <audio>, etc. If you must use the Visual Editor, enter a different DOCTYPE.