Win2D XAML controls leak (along with their parent/siblings) unless removed from their parent #658
Description
A small test app here demonstrates the leak.
The Win2D controls currently retain a strong reference to their parent element (m_lastSeenParent), causing a reference cycle that isn't broken unless they're removed from their parent after it's unloaded. The Avoiding memory leaks doc suggests that this removal is only necessary for a managed app/control that doesn't unsubscribe for events from a Win2D control. This isn't accurate: the parent reference retained in support of the RemoveFromVisualTree method introduces a cycle that may only be broken by calling this method or removing the control from its parent by other means.