Reply To: widening the text frames so they match changed margins

Use the Adjust Layout feature to make text frames resize/move to match what you’re doing with margins.

Ideally, if you’re doing this document-wide, you’d select the parent/pages, then in Layout > Margins and Columns, enter your new measures, and turn on Adjust Layout before you click OK.

If you’ve already changed Margins and Columns, you can use File > Adjust Layout, and enter the new margin measures there. (Don’t adjust page sizes.)