I've changed de Ellipse in the DefaultStyle from an ellipse to a Rectangle.
I've also added a CornerRadius Property to the Magnifier, with a default of 10
I get a rectangular Magnifier with rounded corners, but...
... the properties MagnifierWidth, MagnifierHeight don't seem to get a different value than the default value.
Setting them on de Magnifier doesn't have any effect, neither has setting just Width and Height...
Any suggestions on how to change the dimensions of a rectangular magnifier?