To reproduce: add a RadDiagram and use the following code snippet:

this.radDiagram1.PanToPosition(new Telerik.Windows.Diagrams.Core.Point(10,10));

Workaround: subscribe to the Pan event: 

this.radDiagram1.Pan += radDiagram1_Pan;

        void radDiagram1_Pan(object sender, Telerik.WinControls.UI.Diagrams.PositionChangedRoutedEventArgs e)
        {
        }

The loading time is very slow when there are 100 connections and the connection bridge is set to Bow

Use attached to reproduce. 

 

To reproduce:
- Zoom the diagram and drop an item from the toolbox. 

Workaround:
Friend Class MyToolbox
    Inherits RadDiagramToolbox
  
    Protected Overrides Sub DragDropService_PreviewDragDrop(ByVal sender As Object, ByVal e As RadDropEventArgs)
        'base.DragDropService_PreviewDragDrop(sender, e);
        Dim shape = TryCast(GetType(RadDiagramToolbox).GetField("shape", System.Reflection.BindingFlags.NonPublic Or System.Reflection.BindingFlags.Instance).GetValue(Me), RadDiagramShape)
  
        Dim diagramElement As RadDiagramElement = TryCast(e.HitTarget, RadDiagramElement)
        Dim containerShape As RadDiagramContainerShape = TryCast(e.HitTarget, RadDiagramContainerShape)
        If containerShape IsNot Nothing Then
            diagramElement = containerShape.FindAncestor(Of RadDiagramElement)()
        End If
  
        If diagramElement Is Nothing OrElse diagramElement.Shape IsNot Nothing OrElse shape Is Nothing Then
            Return
        End If
  
        e.Handled = True
        Dim zoom As Double = diagramElement.Zoom
        Dim m As Telerik.WinControls.Layouts.RadMatrix = diagramElement.MainPanel.Transform
        m.Invert()
  
        Dim position = New Telerik.Windows.Diagrams.Core.Point(m.DX + (e.DropLocation.X - shape.Width \ 2) * 1 / zoom, m.DY + (e.DropLocation.Y - shape.Height \ 2) * 1 / zoom)
        If containerShape IsNot Nothing Then
            position.X += containerShape.Position.X
            position.Y += containerShape.Position.Y
        End If
  
        shape.Position = position
        diagramElement.AddShape(shape, Nothing, True)
        If containerShape IsNot Nothing Then
            DirectCast(containerShape, IContainerShape).AddItem(shape)
        End If
  
        shape = Nothing
    End Sub
End Class

Workaround:
 Private Sub RadDiagram1_MouseDoubleClick(sender As Object, e As MouseEventArgs)
        If e.Clicks = 2 Then
            Dim shape As RadDiagramShape = Me.RadDiagram1.DiagramElement.ElementTree.GetElementAtPoint(e.Location).FindAncestor(Of RadDiagramShape)()
            If shape IsNot Nothing Then
                'ToDo
            End If
        End If
    End Sub

To reproduce:

public Form1()
{
    InitializeComponent();

    RadDiagramShape shape = new RadDiagramShape();
    shape.Text = "Shape1";
    shape.AllowCopy = false;
    shape.AllowPaste = false;
    shape.AllowDelete = false;
    shape.AllowCut = false;
    shape.Position = new Telerik.Windows.Diagrams.Core.Point(50, 50);
    shape.BackColor = Color.Red;
    this.radDiagram1.AddShape(shape);
}

Workaround: Hide the first tab in the SettinsgPane as it is demonstrated in the following article: http://www.telerik.com/help/winforms/diagram-settings-pane.html

To reproduce:
- Add some shapes and zoom so only one is visible.
- Export to image.
- The image size is not correct.

Workaround:
private const int InflateValue = 7;
public System.Drawing.Image ExportToImage()
{
    RadDiagramElement diagram = radDiagram1.DiagramElement;
    var enclosingBounds = diagram.CalculateEnclosingBounds();

    using (Bitmap image = new Bitmap((int)(Math.Abs(enclosingBounds.Right) + InflateValue + Math.Abs( enclosingBounds.Left)), (int)(Math.Abs(enclosingBounds.Bottom) + InflateValue + Math.Abs(enclosingBounds.Top))))
    {
        System.Drawing.Graphics nativeGraphics = System.Drawing.Graphics.FromImage(image);
        nativeGraphics.FillRectangle(new System.Drawing.SolidBrush(diagram.ElementTree.RootElement.BackColor), 0, 0, image.Width, image.Height);
        Telerik.WinControls.Paint.RadGdiGraphics radGdi = new Telerik.WinControls.Paint.RadGdiGraphics(nativeGraphics);
        foreach (RadElement element in diagram.ItemsHost.GetChildren(ChildrenListOptions.ZOrdered))
        {
            element.Paint(radGdi, new System.Drawing.Rectangle(int.MinValue / 2, int.MinValue / 2, int.MaxValue, int.MaxValue), 0f, new System.Drawing.SizeF(1, 1), true);
        }

        System.Drawing.Image img = (System.Drawing.Image)image.Clone();
        nativeGraphics.Dispose();
        radGdi.Dispose();
        return img;
    }
}

To reproduce:
- Add some connections and zoom.
- Click a connection
- The event is not fired.

Workaround:
Friend Class MyInputBehaviour
    Inherits DiagramInputBehavior

    Public Sub New(ByVal element As RadDiagramElement)
        MyBase.New(element)
    End Sub
    Public Overrides Function HandleMouseUp(ByVal e As MouseEventArgs) As Boolean
        '  return base.HandleMouseUp(e);
        If Me.DiagramElement.ElementTree.Control.Site IsNot Nothing Then
            Return False
        End If
        Dim elementUnderMouse As RadElement = Me.DiagramElement.ElementTree.GetElementAtPoint(e.Location)
        If Me.IsScrollBar(elementUnderMouse) Then
            Return False
        End If

        If TypeOf elementUnderMouse Is RadButtonElement Then
            Return False
        End If

        Dim position = e.Location

        Dim transform As Telerik.WinControls.Layouts.RadMatrix = Me.DiagramElement.MainPanel.TotalTransform
        transform.Invert()

        Dim transformedPosition = transform.TransformPoint(position)

        Dim service = Me.DiagramElement.Controller.ServiceLocator.GetService(Of IHitTestService)()
        Dim conectionUnderPoint = TryCast(service.GetItemsNearPoint(transformedPosition, DiagramConstants.SelectionHitTestRadius).Where(Function(i) TypeOf i Is IConnection).OrderByDescending(Function(x) x.ZIndex).FirstOrDefault(), IConnection)


        If conectionUnderPoint IsNot Nothing Then
            DirectCast(Me.DiagramElement, IGraphInternal).PublishDiagramEvent(DiagramEvent.ConnectionClicked, New GenericEventArgs(Of IConnection)(conectionUnderPoint, e))
        End If


        Dim mi = Me.DiagramElement.GetType().GetMethod("UpdateFocusedElement", System.Reflection.BindingFlags.Instance Or System.Reflection.BindingFlags.NonPublic)
        mi.Invoke(Me.DiagramElement, Nothing)

        Return False
    End Function
End Class

Change like this:
RadDiagram1.DiagramElement.InputBehavior = New MyInputBehaviour(RadDiagram1.DiagramElement)

To reproduce:
- Add some shapes and call the BringToView method
Private Sub RadButton4_Click(sender As Object, e As EventArgs) Handles RadButton4.Click
    Dim ds As RadDiagramShape
    For i As Integer = 0 To Me.RadDiagram1.Shapes.Count - 1
        If i = 2 Then
            ds = DirectCast(RadDiagram1.Shapes(i), RadDiagramShape)
            Me.RadDiagram1.DiagramElement.BringIntoView(ds, 1.0, True)
            Exit For
        End If
    Next
End Sub

Workaround:
Me.RadDiagram1.DiagramElement.BringIntoView(ds, 1.0, False)

The user is not allowed to add a shape or edit an existing one by using the TextTool: http://docs.telerik.com/devtools/winforms/diagram/diagram-tools/text-tool

Workaround:

 Me.RadDiagramRibbonBar1.buttonTextTool.Visibility = Telerik.WinControls.ElementVisibility.Collapsed

To reproduce:
- Add shape and zoom the view.
- Call the method:
radDiagram1.DiagramElement.BringIntoView(radDiagram1.Shapes[0]);

Workaround:
radDiagram1.DiagramElement.BringIntoView(radDiagram1.Shapes[0],radDiagram1.Zoom, false);          

How to reproduce: 

 public partial class Form1 : Form
 {
     public Form1()
     {
         InitializeComponent();

         RadDiagramShape shape1 = new RadDiagramShape()
         {
             Text = "Second Level Domain",
             ElementShape = new RoundRectShape(4),
             BackColor = Color.LimeGreen
         };
         shape1.Position = new Telerik.Windows.Diagrams.Core.Point(100, 100);
         radDiagram1.Items.Add(shape1);

         var res = radDiagram1.Items[0];
         ((Telerik.WinControls.UI.Diagrams.RadDiagramItem)shape1).EndEdit += item_EndEdit;

         RadDiagramShape shape2 = new RadDiagramShape()
         {
             Text = "Top Level Domain",
             ElementShape = new RoundRectShape(50),
             BackColor = Color.Cyan
         };
         shape2.Position = new Telerik.Windows.Diagrams.Core.Point(1600, 100);

         radDiagram1.Items.Add(shape2);

         RadDiagramShape shape3 = new RadDiagramShape()
         {
             Text = "Organization Domain",
             ElementShape = new RoundRectShape(20),
             BackColor = Color.Yellow
         };
         shape3.Position = new Telerik.Windows.Diagrams.Core.Point(2400, 100);
         radDiagram1.Items.Add(shape3);

         RadDiagramConnection connection1 = new RadDiagramConnection() { Name = "connection1" };
         connection1.Source = shape1;
         connection1.Target = shape2;
         radDiagram1.Items.Add(connection1);

         RadDiagramConnection connection2 = new RadDiagramConnection()
         {
             Name = "connection2"
         };
         connection2.Source = shape2;
         connection2.Target = shape3;
         radDiagram1.Items.Add(connection2);
     }

     private void item_EndEdit(object sender, Telerik.WinControls.UI.Diagrams.RadRoutedEditEventArgs e)
     {
         RadDiagramShape shape = ((RadDiagramShape)sender);
         string txt = shape.Text;
         Size size = TextRenderer.MeasureText(txt, shape.Font, new System.Drawing.Size( (int)shape.Width, int.MaxValue ), ~TextFormatFlags.SingleLine);

         shape.Height = size.Height;
     }

     private void radButton1_Click(object sender, EventArgs e)
     {
         this.radDiagram1.DiagramElement.BringIntoView(radDiagram1.Items[0], this.radDiagram1.Zoom, false);
     }

     private void radButton2_Click(object sender, EventArgs e)
     {
         this.radDiagram1.DiagramElement.BringIntoView(radDiagram1.Items[1], this.radDiagram1.Zoom, false);
     }

     private void radButton3_Click(object sender, EventArgs e)
     {
         this.radDiagram1.DiagramElement.BringIntoView(radDiagram1.Items[2], this.radDiagram1.Zoom, false);
     }
 }

Workaround:  manually update the view
private void radButton1_Click(object sender, EventArgs e)
{
    this.radDiagram1.DiagramElement.BringIntoView(radDiagram1.Items[0], this.radDiagram1.Zoom, false);
    this.radDiagram1.DiagramElement.Controller.OnViewportChanged();
}

private void radButton2_Click(object sender, EventArgs e)
{
    this.radDiagram1.DiagramElement.BringIntoView(radDiagram1.Items[1], this.radDiagram1.Zoom, false);
    this.radDiagram1.DiagramElement.Controller.OnViewportChanged();
}

private void radButton3_Click(object sender, EventArgs e)
{
    this.radDiagram1.DiagramElement.BringIntoView(radDiagram1.Items[2], this.radDiagram1.Zoom, false);
    this.radDiagram1.DiagramElement.Controller.OnViewportChanged();
}

Workaround call the InitializeDiagram method in the OnLoad method of the form.

protected override void OnLoad(EventArgs e)
{
    base.OnLoad(e);
    this.InitializeDiagram();
}

By default, when you bind RadDiagram, RadDiagramShape items are created by the DiagramDataLayer. It would be nice to have the possibility to replace the DiagramDataLayer for example and override its CreateDiagramShapeItem method to use custom RadDiagramShapes.

To reproduce: 
1. Add a RadDiagram to the form and open its property builder at design time. 
2. Add a RadDiagramShape and set some value to the shape's Tag property.
3. Save the changes and exit the property builder.

When you run the application you will notice that the Tag property of the shape is not stored. 

Please refer to the attached gif file illustrating better the observed behavior when using the UI to add and connect shapes.