Change theme color of opening curly brace highlighting

Meaning, when the cursor is positioned on a '}' and the opening '{' is associated with something like a function name or switch, if, etc. and that opener is above the visible page, the IDE puts up a highlighted version of the containing line at the top of the listing, printing over the tab with the current file name.

What is the IDE theme name/value which controls the foreground/background colors of this highlighted text?

In your theme folder, there is a folder named syntax. In that folder there is a document named default.

The aspect of the GUI that youre concerned with is governed by code in this document. (For some reason the GUI reads several documents to decide what colors to show. Its a bit messy) Most other aspects are in theme.txt

Look for this part:

<matchedBracket - Highlighting of the bracket matched to the one at the cursor position.

   fg= - Doesn't appear to have any effect.
   bg= - Matched bracket highlight background color.
   highlightBoth= - Doesn't appear to have any effect.
   animate= - Animation on matched bracket highlighting

I was able to find this with the help of old posts by @pert

Edit: I have just discovered that the brace (and parentheses) highlight colors are driven from both the “default.xml” and “theme.txt”. At least on my computer (Windows 10 with latest release of Arduino IDE). I assume this will change when someone decides to merge the documents.

Thanks for the reply! I was thinking I'd have to bump to get a response.

Just to make sure we're on the same page, the color of the background of the circled box is what I'm interested in changing. Matching bracket, etc. character highlighting is working and is satisfactory.

I have seen and edited the theme file - as can be seen in the posted picture. I tried to edit the default file but the Win10 won't give write access. Is there a way around this?

dougp:
Just to make sure we're on the same page, the color of the background of the circled box is what I'm interested in changing.

Unfortunately, I don't know about this.

dougp:
I tried to edit the default file but the Win10 won't give write access. Is there a way around this?

There are certainly ways of getting write access. However, it's really not a great idea to be writing to files in the Arduino IDE installation folder anyway, because you'll need to do it all over again every time you update to a new version.

Fortunately, there is now support for storing IDE themes in the sketchbook folder, where they will persist through IDE updates.

I have documented the two options for installing themes to the sketchbook folder here:

Let me know if you have any trouble with that.

pert:
I have documented the two options for installing themes to the sketchbook folder here:

Thanks! Simplifies things muchly! Still unsure about the box highlights. I'll just have to Easter Egg my way through the settings, not knowing the name of the feature.

You're welcome. It really is a nice feature.

The readme of this project contains everything I know about the IDE's theme system:

This was written before both the sketchbook installed theme and tooltip features were added. You might be able to use that documentation to eliminate a lot of the theme properties from your easter egg hunt. If you do use it and you discover any additional information, please let me know.

I cannot find the control for the matching bracket info box. Be nice if the developers could throw a bone now and then.