Quoted from Aurich:
Testing it with Safari on OS X.
Edit: Resizing the window seems to work fine.
I'm on an 11" screen, so perhaps blow up the font big to compensate if you are on a bigger screen.
1. click edit, scroll window up so that "edit post" is near top of browser window.
2. zoom in on your browser until the edit window is 1/2 the size of the screen vertically (command + "-")
3. click-hold at bottom right corner of screen
4. drag down to resize it bigger
5. notice whole page "jumps" down, and the edit window moves an entire window height AWAY from "edit post up top"