Reset a property to its default value
Resetting a property to its default value is useful if you want to use the default value of the object type. For example, if you convert a canvas panel to a grid panel, you might want to reset the Layout properties to the defaults that are used by a grid. Using default values reduces the size of your XAML files because default properties do not have to be specified as XAML attributes.
In the Properties panel, locate the property that you want to reset.
Next to the property, click Advanced property options . The color of the marker depends on what the property was set to. For example, a yellow marker means that the property was data bound.
On the shortcut menu that appears, click Reset.
The value field is updated to show you the default property value.