Not sure if I'm missing something, but in beginning to make a custom display template, I simply copied over "fm-summary-multi.php," and renamed it *****-custom.php.
Made one modification -- I took out the line that displayed the respondent's IP address -- and saved it.
I chose that new template (which I gave a different name) from the drop-down.
Reloaded the data results page (a new public page using a shortcode, not the submission data tab on the dashboard).
Nothing changed. The IP address line was still there. What am I missing?