The object filter for an external application determines for which managed objects a user can launch the external application. The Object Filter is the set of filter conditions that each managed object you have defined is compared against. It might help to understand filter conditions if you think of them as rules. Each "rule" you create allows the external application to be launched for those managed objects that satisfy the rule. The Object Filter property also controls which external applications appear as a selection in the Default Action properties in the Managed Objects node.

See Defining the Object Filter Property for more information.