Backing out of a half-written document can now offer to keep it rather
than bin it, emitting DraftRequested with the document; the close control
can be the glyph full-screen composers use.

Video cards show a real frame instead of a grey placeholder.

Two poll bugs found by running every content combination through the
editor: the length the author chose was never saved, and blank answers
were. Both are covered by parity harness cases now.