EXFO FTB-8500 Series for FTB-200 - Manual (Page 197)

Traffic Analyzer Tabs
Ethernet and Fibre Channel Application 183
Traffic Filter Configuration
Filter in use for data capture
The message, Filter in use for data capture, is displayed to indicate that
the selected filter is in use by the capture tool. See Filter on page 189 for
more information.
Note: It is not possible to modify or disable a filter that is already in use for
capture.