# HPE: Manage Events

From the Project Menu, select Manage Events... or from the toolbar, click on the Manage Events button . This will open the Project Event Set window.

The Event Manager in the HPE is based on the FPE version. However the rules governing the project event set and its construction are more complex. Subsystem can only contain default events and interface events (Request, Answer, and Low data events) from eligible interfaces. Interfaces can only contain request, answer or low-data events. A high-level subsystem is allowed to contain interface events from any interface but a low-level subsystem is only allowed to contain interface events from the interface it implements. The default events each subsystem contains must be pair-wise disjoint from those of other subsystems. Every interface event must belong to exactly one interface.

When any of these rules are violated, the tooltip that is displayed when hovering over a project event will not only display the event properties but also any errors associated with the event. An event that has conflicts is displayed in red. An example of such tooltip is shown below.

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