This is almost like the Property Trigger, but here it is used to set an action on multiple property changes, and will execute it when all the conditions within the MulitTrigger.Conditions are satisfied. The MultiTrigger object hosts a collection of these Condition objects.
Here, in this example, we have MultiTrigger associated with TextBox controls. When the control is enabled and gets keyboard focus, it changes its Foreground and Background properties. When either of them is false, it returns the property values to its original state.