Filter not working on Showplan XML in SQL Server trace
SHOWPLAN XML event does not have a column with cpu duration so you cannot filter by duration. You can only filter by columns mentioned in this article.

https://docs.microsoft.com/en-us/sql/relational-databases/event-classes/showplan-xml-event-class

Few alternatives:


use filter by other allowed columns.
capture everything for as minimum time as practical, load in table and filter. Be careful about load generated by this process, especially on production server. 
Trace for long running queries. Use that list to filter SHOWPLAN XML  event.