Thank you for solving a mystery for me! I couldn't understand why I could never find the Editing Mode on the Create-a-Post page. It's because as soon as I open that page up, I start typing and, as you pointed out, the option then goes away.

I still find the mix of markdown and html glitchy, and particularly have trouble with centering just a portion of a post, then using </center
yet it won't stop centering everything following. I have this problem in about every 3rd or 4th posting I do.

But anyway, thanks for solving the mystery of the missing editing button!