The marker position search function, by default, can be initiated by any press of the search key. Search tracking mode performs continuous marker position search, until this mode is disabled.
Marker Search Properties
To enable/disable search tracking mode:
Search > Properties > Tracking [On|Off]
CALC:MARK:FUNC:TRAC
Sets or reads out the target value when the marker target search is performed by the CALC:MARK:FUNC:EXEC command.