Problem with subtitles

[defaulte9t93bdtciwt]

I am writing subtitles to a work using the Captions tool. After a while, the "black box" highlighting the subtitles disappeared for all new text lines. This makes the text close to impossible to read. How do I return the black box to the subtitles again? 

[Stan Jones]

A screenshot would help. Are you talking about the background box? 

What version of PR are you using? There was a major change in the captions workflow beginning in PR 2021.

Stan