Problem: How to add a Custom Filter by Author in Views?
Solution: Toolset Post Views cannot have Custom Filters for Post authors. Only Query Filters are allowed on this parameter.
To Create a Custom Filter where the user can choose from the front end the Author of a Post so to filter the list by this value, you need to create a Custom Field or taxonomy and update your Posts with this new values.
As an example you could create a Custom Field (single line text field) where the author name can be entered on each post. Then, by this, you can have a Custom Front-end Filter.
There is a request filed to allow the Front End searching by Authors, but this is not implemented yet.
This is the technical support forum for Toolset - a suite of plugins for developing WordPress sites without writing PHP.
Everyone can read this forum, but only Toolset clients can post in it. Toolset support works 6 days per week, 19 hours per day.