When I have a column that only allows one person, the filter in the gallery works. I have done this multiple times, but that solution will not work when more than one can be selected. I've tested that theory by selecting more than one person allowed in a column (which was originally set to only one person or group) breaking the ability to filter (errors). I can then reset that same column to a single selection and refresh the data source, and it works again. I've done this with sever columns of this type.
Filter('My People Column',
StartsWith('Project Manager'.DisplayName, txtPerson.Text)
)
When I change the column to a multi-selection column then the StartsWith section just says it has some invalid arguments.
Thank you
Patrick