Ensure all significant UI interactions trigger redraw

[nmwsharp]

Right now, there are lots of small bugs where changing some setting in the quantity option pane doesn't trigger a redraw when it should (e.g., changing bounds on colormap). This is caused by missing requestRedraw() calls.

Part 1 is do a quick audit to identify and fix as many of these as possible.

Part 2 is to make these bugs less common in the future. There's probably no magic solution, and this will probably be a recurring issue. But we should do what we can, like abstracting more things behind helpers, to make it less common.