XUL Talk:Slider Tag
From MozillaWiki
I think it's counter-intuitive that the slider in vertical mode should have up/pgup decreasing the value...
An example would be a volume control - it would be weird to drag the thumb downwards to increase the volume, instead of turning up the volume by pressing the up arrow...
Examples of situations where "up" is intuitive for "decrease" are appreciated...
Agreed
Totally agree.