The progress fill amount displayed on the referenced node's accent bar, expressed as a percentage.
Accepted values range from -100 to 100. A positive value fills the bar from left to right.
A negative value fills it from right to left. A value of 0 hides the bar.
Setting this property has no effect when the NodeReference has no associated NodeReference.Context, such as when it is default.
Throws ObjectDisposedException when you access this method after you call Context.Dispose on the context.