The inline editor fields were appearing very short on Firefox when set

to have buttons appear on the following line. This was due to our

calculation for whether buttons were on the next line, in combination

with however Firefox is representing coordinates and sizings.
Instead of trying to be fancy and detect things like the buttons

wrapping to the next line, we're now just checking the 'display'

property of the buttons. If it's 'inline' or 'inline-block', we'll

factor in the size. Otherwise, we won't. It's up to the caller to ensure

that the right 'display' is set and that elemens either wrap or don't.

Tested with multi-line editors, and with single line.
For single line editors, I tested with buttons display set for 'block',

'inline', and 'inline-block.' These were tested on Chrome and Firefox.