Reply To: Coloured box around selected text without using frame tool

Well, it works:

— but with some minor caveats. It seems the default top offset, 0 (in your preferred units of measure), aligns with the baseline of the first line. So you have to adjust for the line height yourself — by eye, because InDesign's line height does not start on the baseline but a little below. It's similar to the “Top Paragraph Rule” in that aspect.

Another one is that the added definitions don't appear in Tagged Text Export, INX, or IDML.

And another one is that you can only apply it per paragraph style, trying to access it with the Paragraph panel pops up a friendly alert saying “In Next Version” :)

But– it does What It Promises! Edit the text inside the box/border to make it more or less lines long, and the box automatically adjusts!