Diagram Shapes' property is bound to property from the ViewModel.
Case 1) Using GraphSource =>Shapes DataContext is automatically apllied. GraphSource is set to null or changed.
Or
Case 2) Not using Graphsource. Shape's DataContext is set manually (in code behind). Diagram.Clear() is invoked.

Result: Binding Expression erors in Output indicate missing properties - these are bound properties of the shapes.

ManipulationAdorner (including Rotation thumb, resizing thumbs) should not be zoomed along with the shape.

Currently the Bezier Connections Start,End Points and the two editing points are created in a common Canvas. There is no mechanism to hide the editing points but show the start and end point.
Note: Currently there's a way to hide editing or intermediate points - you'll need a style and a converter. We've added a new SDK example (HideBezierHandles) demonstrating this.

PathTool: Possibility to edit the shape path via edit points like the Pen Tool in Blend.

Implement support (or extensibility) for printing the whole diagram in a single page.

Ability to export a diagram to PDF.

Import from DWG files needed.

Research and improve the virtualization performance. Currently, the virtualization in the diagram creates containers for all shapes and sets the Visibility of the containers outside of the viewport to Collapsed. This saves from the layout and rendering performance, but it is not optimal. Consider implementing a standard virtualization mechanism which adds containers in the visual tree only for the shapes within the viewport.

User scenario:
When zooming out on more than 500-600 shapes and then panning, if telerik:DiagramSurface.IsVirtualizing="True", the performance is slower. When virtualization is off, the performance is a little better.

Add spell checking to the shape and connections, while editing

Introducing Page size (A4, etc) concenpt and vertical and horizontal rulers

Extend RadDiagram to support natively Venn Diagrams.