A double-click on a slider's name or thumb already reset it, but nothing said so: only the value had a
tooltip. Resting the pointer on the name or on the thumb now shows "Exposure — double-click to reset
it", the wording (and translations) the curve channels already use. The rest of the track, which is
clicked and dragged, gets no tooltip, and the value keeps "Click to type a value".
The first click of a double-click on the thumb moved the value to where the pointer landed, a few
points off its centre: one history step, then the reset another. A click on the thumb now leaves the
value alone, so the reset is one undo step, as from the name. A disabled slider's name no longer
resets it.
No per-slider reset button: Lightroom has none, and the double-click it documents is now shown where
it works. Tests: tests_slider_reset.rs (name and thumb reset Exposure and Contrast in one undo step,
the hints, a click on the thumb keeps the value, typing a value still works) and
widgets/tests_slider_reset.rs (a disabled slider's name).
Atmik Shetty
cb8b797cd4