When drawing in the sprite editor, left click draws and right click picks up the color under the cursor (like the eye dropper in other image editing tools).
When using the bucket fill tool, left click fills and right click... fills. It would be convenient and consistent if right click was still an eye dropper in this scenario.

@sparr, you are not the only one with suggestions, and yes, this was already suggested.

https://www.lexaloffle.com/bbs/?tid=35330