When overridden in a derived class, positions child elements and determines a size for a FrameworkElement derived class.
Assembly: PresentationFramework (in PresentationFramework.dll)
Control authors who want to customize the arrange pass of layout processing should override this method. The implementation pattern should call Arrange on each visible child element, and pass the final desired size for each child element as the finalRect parameter. Parent elements should call Arrange on each child, otherwise the child elements will not be rendered.