+ /**
+ * @brief When a custom wheel event occurs, it need to process the focused actor first.
+ *
+ * Therefore, KeyboardFocusManager first checks whether WheelEvent is generated as WheelEventGeneratedSignal.
+ * After that wheelEventProcessor must invoke WheelEvent only if wheelEventGeneratedSignal () is not consumed.
+ *
+ * This is only valid for custom wheel events.
+ *
+ * A callback of the following type may be connected:
+ * @code
+ * bool YourCallbackName(const WheelEvent& event);
+ * @endcode
+ *
+ * @return The return is true if WheelEvent is consumed, otherwise false.
+ */
+ WheelEventGeneratedSignalType& WheelEventGeneratedSignal();
+