Node events occur when a change happens to a node, or data associated with a node such as an Attribute. The different types of node events are identified by the enumeration: NodeEventType. The node events are:

• Value of an attribute is changed
• An attribute is relinked to another attribute
• A new attribute is linked or removed.
• When the target node of the pointer is changed (See Node::ContentChanged())
• The target node of the pointer is about to destroyed.
• Status of the attribute is changed (See Attribute::SetConst()).
• UI data in attributes are changed.
• Dialog UI refresh

A node event can be handled in a class derived from Node by overriding the virtual function: Node::OnNodeEvent. The Node::OnNodeEvent receives a constant reference to an object of type EventGate. The EventGate type is equivalent to the type aevent.

Event gates can be used for triggering (emitting) or receiving events. An emitter gate can be connected to a receiver gate via the EventGate::Connect() member function. Multiple receiver gates can also be connected in sequence, where each receiver acts as an emitter for any events it receives. An event gate derives from Attribute.