Hints for occurences highlights to work properly

[Lauloque]

AFAIK the cause of the issue is how Blender handles text (see #139761 - Blender Text Editor Font Display Issue - blender - Blender Projects), but the occurences highlight on selection essentially isn't usable when using odd numbers of font size in the text editor:

Perhaps a little help about that could be as simple as adding a hint in the GUI:

Maybe even below the text editor's font size property.

[DesignLipsx]

I merged the pull request. The issue stemmed from the alpha value being set to 0.3 for the blue color, while other colors had full opacity. I've fixed the opacity issue, so the next version will have a much better visual result.
However, there will still be a small problem due to the Blender font size issue.