The Link Action lets you re-use parts of a Virtual User across your load testing project.
Fragments Virtual User contains actions that can only be executed at runtime by being linked using Link actions.
In the above screenshot the link action will be replaced by the container Home Page of the virtual user Test Fragment.
Simply select a container action in the tree to have it injected in place of the Link Action during test execution.
Only container actions present in a Virtual User of type Fragments can be selected.
Click on the Open Link button bellow the linked action tree or directly on the magnifier icon on the upper right corner of the action to go the the linked Virtual User / Action.
When validating a virtual user you can see the debug result by using this Open Link button.
Be aware though that directly opening the linked Virtual User from the design page will not display debug results.