Any resolution for this? Having the same problem.

 

I try to paste HTML code into the editor whilst on the HTML tab. The Paste as Plain Text modal window opens, and I can paste into that, but when I click Insert, it doesn't insert the code; it inserts formatted rich text rendered from the code. When I save or switch back to the "Normal" tab, it treats the rich text as HTML code, and I lose all formatting and tags.