The task flow contains three view activities:
stock, and three control flow cases. The first activity you dropped is the default, as indicated by the green halo or circle. Currently the task flow does not do anything: the
! icon on each view activity indicates that the view activity is not bound to any page. Later you will tie a page to each view activity, and add navigation.
You can see the rules that JDeveloper has added to the task flow file using a visual format by clicking the
Overview tab at the bottom of the editor window and selecting the
Control Flows navigation tab at the left, for example:
You can see the same rules in the XML source of the task flow file by clicking the
Source tab at the bottom: