357552 - Improve combobox dropdown menu sizing in some rare cases

Status: NEW

(Core :: Layout: Form Controls, enhancement)

Description

[Mats Palmgren (inactive)]

Improve combobox dropdown menu sizing in some rare cases.


In bug 314939 comment 15, I wrote:
I'm not so sure "availDropHeight = screenHeight/2 - heightOfARow*2" is a good
heuristic. Zooming a dropdown menu to ~1000% makes it two rows high
(1600x1200 screen) when it could easily fit 4 or 5 rows on half the
screen height. "screenHeight/2 - heightOfARow/2" or even
"screenHeight/2 - 30px" or something might be better in general...

In bug 314939 comment 16, bzbarsky wrote:
> I'm not so sure "availDropHeight = screenHeight/2 - heightOfARow*2" is a good
> heuristic.

It's not.  The right heuristic is height of a row plus the parent reflow
state's computed border+padding-top/bottom, I'd think....  or maybe even factor
in the parent reflow state's computed height?