Ability to show invisible characters in caption box

[Kevin M. Cox]

I'd love the ability to show invisible characters, like can be enabled in a word processor or text editor, in the caption box.

This would help avoid accidental entry of double spaces which can easily happen, with no way to tell visually, at right edge of the caption box when the line wraps.

Looks like this was also requested back in 2008.
https://forums.camerabits.com/index.php?topic=2682

[alexmacnaughton]

I agree that highlighting double spaces would be a useful feature.