Allow selection of collapsed values without triggering expansion

[tmcw]

This ports some clever logic from devtools ( https://github.com/ChromeDevTools/devtools-frontend/blob/7fbe24c094a53d6a95cbb0d19b4bf889c7dcee53/front_end/dom_extension/DOMExtension.js#L271 ) that that essentially says that if you click on something toggleable and the thing has a selection, then it won't be expanded. This works because:

1. If you just click on it, it expands.
2. If you select it, it doesn't expand (it has a selection)
3. If it's selected and you click on it, the selection is zapped immediately and it expands.

[mbostock]

For context, the reason we’re using mouseup instead of click is that in our inspector, the value you’re inspecting can change up to sixty times a second, and if it changes between mousedown and mouseup, a click event isn’t generated. Will the approach still work with values that change?

[tmcw]

Got it - the change from mouseup to click ended up being extraneous anyway: I've switched it back. This approach (no approach) could make it easier to select quickly-changing values, but that's not a change from existing behavior.

[mbostock]

Cool, glad the new technique still works! 👍