When I make button images, I try to make sure if icons on buttons are located at the same position between multiple states of the buttons.
( However, whether the icon has different color or effect to show that the button is pressed are different. )

The measure tool to get distance from edge of image helps a lot under that situation. But I would like to compare distances from this image and that image.
Although I can write down those, it can be good that the measure tool still shows distance when I click another window to measure and compare.