Using the attached solution:
(1) Add an Xceed license key into the source code
(2) Start up the application
(3) Click the "Float la1" button
(4) Click OK through the MessageBoxes to show that the PreviewFloat and Floated events are properly firing
(5) LayoutAnchorable (la1) is now floating as expected.
(6) Click the 'Dock la1" button
(7) No MessageBoxes are presented which shows that the PreviewDock and Docked events are not firing when the la1.Dock() method is used.
(8) LayoutAnchorable (la1) is now docked as expected.
(9) This sample solution does not test LayoutAnchorable.DockAsDocument(), but in my production application, that also does not cause these events to fire.
If possible, please include a fix for this issue in an update to v4.5 of the WPF Toolkit Nuget package soon.