This is great, thanks for this feature. However, I have a suggestion for improvement in section #Multiple highlights, blended colors. Currently it says:
When a given edit is highlighted by more than one color (because it possesses more than one highlighted property), the system highlights that edit with a blend of the relevant highlight colors. For example, yellow and blue highlights will blend to make green.
I think this is a mistake. When I see "green", although I'm well aware of primary color mixing, I don't automatically think, "yellow" and "blue"; at least, not without some brief delay to stare at the color, and decide if this is a "highlight" color, or a combined one that needs to be parsed. (And what if it's a combo of three, do I need even finer abilities of instantaneous color mix disassembly algorithms running round my brain?) Besides the slight pause that goes on, this is also extra work for the brain to interpret.
I would like to suggest a different approach, which should give an instantaneous recognition of multiple colors, and which doesn't require a user to parse/disassemble blended colors into two (or more) colors in my head, namely, [https://developer.mozilla.org/en-US/docs/Web/CSS/linear-gradient() css linear gradients].
I see this as involving revision line background colors that are mostly solid color, as you have now, but instead of running the whole width of the revision line, they would run only for part of it. For a line highlighted by one blue and one yellow filter, the background gradient would be solid blue for roughly 50% of the line width, and yellow for the second half. For esthetic reasons, rather than a sharp divider with no transition, there should be a slight blend-transition at the border, maybe 1-6%, so rather than 50-50, the gradient would be something like, 48% blue, 4% blue-yellow gradient, 48% yellow. For lines having a blue, yellow, and orange background due to 3 filters, about 32% width of solid color for each one, with two blend-transitions of ~2% each. For two blues, a yellow, and an orange, it would be 48%, 24%, 24%, with two blend transitions. I'll try to mock up something later as an example to show you what I mean. (ping please!) Thanks, ~~~~