If I click and drag
So it becomes
and I want to reset it to it's original value (1000px), clicking the mouse-wheel on the value should do that. I think the mouse-wheel button is a good choice, because it feels natural and convenient including other software that use the same button to achieve a reset.
I don't want to click and manually type 1000px again.
I don't want to refresh for a quick fix (have other values that are adjusted).