find all messages in threads where one message matches

[Francesco Ariis]

Hello Ben,

On Sat, Nov 03, 2018 at 04:45:42PM -0400, Ben Fitzgerald wrote:
> is there any way to tag all messages in all threads where a search pattern
> matches one more messages in a thread?

Sure, try

    ~(~f Ian)

to get every thread were Ian posted a message. Is that what you want?