Editor: Hilite all occurences of selected word

I would really like to edit all of my sketches in Arduino. There is one major feature, that I miss, when using the built-in editor: hilite all occurences, of the text I just selected.

It doesn't need to be just variables, that are hilited - it can be just anything (even comments) that have the same chars in it.

Even nearly all modern editors offer this feature, I like BB Edit on Mac most, because it hilites every occurence.

No file or test is identified in the issue. Start by locating the Arduino IDE 1.x built-in editor implementation, then determine how selected text is represented and how editor highlighting is handled; done means every occurrence of the selected characters, including in comments, is highlighted.

Written by the indexing model from the issue text.