The theme editor needs to be simplified. My problem stems from white text/objects on a black background which is hard for me to read. In order to reverse this, I found the theme editor to be overly complex. I mostly fixed this but constraints in details is not configurable, nor blueprints.
My suggestion is that all text should have one color setting actually.
Also things should be categorized by UI feature like panel, header, dropdown, etc, where each has a foreground and background color setting for each type of visibility.
Example for panel:
