Version 3.5.3 of WPF Diagram control contains the following new features and improvements -

Layout improvements
~ The KeepLinkShapes property of LayeredLayout lets you preserve initial Shape value of links when LinkType is set to Cascading. The orthogonal path applied by latter property is approximated using respective link shape.
~ Set ConsiderNodeShapes property of LayeredLayout to align link end points to non-rectangular node borders.
~ Fix for wrong link positions when the diagram contains folded containers.
~ Fix for unnecessarily large distance between subsequent layers after a long node appears in a layer.
~ ArrangeAsync method of CompositeLayout now also applies MasterLayout asynchronously.

PathFinder improvements
~ Speed of FindAllCycles and EnumAllCycles methods improved.
~ FindAllCycles and EnumAllCycles no longer report mirrored versions of cycles in undirected mode.

Miscellaneous
~ Z order of ContainerNode's children is now local to the container. Adding child node to a container no longer changes ZIndex values.
~ The Compact method of Diagram class moves nodes as far possible to the top or left sides of diagram without changing their initial relative positions.
~ The ExtendSelection element of ModifierKeyAction lets users select items with lasso rectangle without deselecting old ones.
~ Set Selection.KeepInsideDiagram property to prevent users from dragging multiple selection outside of diagram boundaries.
~ Fix for incorrectly exported Procedure shape by ExcelExporter.
~ Fix for link auto-routing around rotated DiagramNodeAdapter objects.

If anyone is interested in trying the beta version, please download this archive containing updated assembly files -
https://mindfusion.eu/_beta/wpfdiag353.zip

Any comments, questions and general feedback are welcome.