Wpf binding not updating textbox
As of writing, all properties except for the Text property, is updated as soon as the property changes (Property Changed), while the Text property is updated when focus on the destination element is lost (Lost Focus).
This property can is set to an object to use as the source for its data bindings and those of its children.
This behavior is controlled by a property on the binding called Update Source Trigger.
It defaults to the value "Default", which basically means that the source is updated based on the property that you bind to.
The problem here does not lie with the Full Name property.
If you were to call it you would see the correct, updated full name.
We saw this with a Slider and a Text Block that were bound to the same value.