Editor Preview is incomplete and out of date #1072
Description
The preview that you get within the page is out of date with modern firefox's appearance and does not accurately depict the result.
This is somewhat mitigated by the user's active theme being modified on the fly, but it's often difficult to track down what UI elements get colored in what context based on the name alone, with some elements appearing in the preview but not affected by "advanced colors".
It could make sense to update the preview to reflect the current firefox appearance, and add a preview for inactive windows, sidebar colors, etc.