gradient mid stop, arrowkey movement distance and direction related to the page corner

The distance the start of a linear or radial gradient is from the bottom corner of the page
determines how far and in what direction (away from the bottom corner of the page)
a mid gradient stop moves when an arrow key is pressed.

Open the attached file,
choose the gradient tool,
select one of the rectangles,
then the mid gradient stop,
press either the up, down, left or right arrow key,
repeat for all the mid gradient stops on all the rectangles,
the mid gradient stop moves away with a distance that's based on
how far away the start of the gradient is from the bottom left corner of the page.

It seams to only effect the mid gradient stops,
the start and end gradient stops move 1px with the arrow keys,
and 10px when shift is held down and an arrow key is pressed.

Tested with:
r12841 on linux mint 15 cinnamon 32bit