I have an idea. I think if there is a certain feature in the editor, then editing can be REALLY easy. The code can be very easy to locate.
The feature is, that the font of the code that starts in a parentheses or brace, picks up a color automatically. So anywhere there is a code in brackets, the color of the font is other than the normal black (or whichever is the default color, chosen in options). The color of the brackets is the same as their code.
So if there is a scenario, where there is a set of another brackets in already one, then the color of the new code (in the inner brackets) would be a new one. Eg: (blue (red) blue).
Another option would be to have the inner brackets choose alternate colors in their characters, with colors comprising of external and inner brackets (or more colors if there are more brackets). But that should be disturbing I think.
First I had written about the inner brackets taking the blend of the two colors, eg: (blue (violet-- because of original red taken by these brackets) blue). But then I thought that here, the inner brackets have a violet code. If a nearby further code in its first set of brackets happens to take the same color-- violet-- then there would be confusion.
Care needs to be taken, so that the fonts do not take colors that won't be visible in the background. Especially if there is an option to choose the background colors too.
Right idea for the right chapter: I am on "Control Structures"!