I really like the full screen HTML editor and I love the small menu that drops down when the mouse is moved to the top of the page which displays the UPDATE button and other options.
My request/suggestion is that you add a PREVIEW CHANGES button to this menu. When I am working in full screen mode and want to check that I am entering code properly, I have to transfer back into the normal mode, click the preview button, and then click back to the full screen mode to keep working. If a PREVIEW button were added, then I could work in full screen mode all the time and get more done faster.
I hope you will consider making this addition.