I was reviewing the control functionality with your WinForm Floor Plan demo, when I discovered a repeatable bug.  If I select the chair to the left of the sofa (shown in screenshot below) and click the setup icon, it works fine.  However, if I rotate the chair prior to clicking the setup icon, i get the error shown below.  The error is repeatable.

***************************************************

BEGIN ERROR TEXT

***************************************************

See the end of this message for details on invoking 
just-in-time (JIT) debugging instead of this dialog box.

************** Exception Text **************
System.ArgumentOutOfRangeException: Value of '613' is not valid for 'Value'. 'Value' should be between 'Minimum' and 'Maximum'.
Parameter name: Value
   at Telerik.WinControls.UI.RadSpinElement.set_Value(Decimal value)
   at Telerik.WinControls.UI.RadSpinEditor.set_Value(Decimal value)
   at Telerik.WinControls.UI.RadDiagramSettingsPane.SetupControls()
   at Telerik.WinControls.UI.RadDiagramSettingsPane.ShowPopup(Point location, RadDiagramElement diagramElement)
   at Telerik.WinControls.UI.RadDiagramSettingsPane.Show(Point location, RadDiagramElement owner)
   at Telerik.WinControls.UI.RadDiagramElement.additionalContent_Click(Object sender, EventArgs e)
   at Telerik.WinControls.RadElement.OnClick(EventArgs e)
   at Telerik.WinControls.UI.RadButtonItem.OnClick(EventArgs e)
   at Telerik.WinControls.UI.RadButtonElement.OnClick(EventArgs e)
   at Telerik.WinControls.RadElement.DoClick(EventArgs e)
   at Telerik.WinControls.RadElement.RaiseBubbleEvent(RadElement sender, RoutedEventArgs args)
   at Telerik.WinControls.RadItem.RaiseBubbleEvent(RadElement sender, RoutedEventArgs args)
   at Telerik.WinControls.RadElement.RaiseRoutedEvent(RadElement sender, RoutedEventArgs args)
   at Telerik.WinControls.RadElement.DoMouseUp(MouseEventArgs e)
   at Telerik.WinControls.ComponentInputBehavior.OnMouseUp(MouseEventArgs e)
   at Telerik.WinControls.RadControl.OnMouseUp(MouseEventArgs e)
   at Telerik.WinControls.UI.RadDiagram.OnMouseUp(MouseEventArgs e)
   at System.Windows.Forms.Control.WmMouseUp(Message& m, MouseButtons button, Int32 clicks)
   at System.Windows.Forms.Control.WndProc(Message& m)
   at System.Windows.Forms.ScrollableControl.WndProc(Message& m)
   at Telerik.WinControls.RadControl.WndProc(Message& m)
   at System.Windows.Forms.Control.ControlNativeWindow.OnMessage(Message& m)
   at System.Windows.Forms.Control.ControlNativeWindow.WndProc(Message& m)
   at System.Windows.Forms.NativeWindow.Callback(IntPtr hWnd, Int32 msg, IntPtr wparam, IntPtr lparam)


************** Loaded Assemblies **************
mscorlib
    Assembly Version: 4.0.0.0
    Win32 Version: 4.7.3740.0 built by: NET472REL1LAST_C
    CodeBase: file:///C:/Windows/Microsoft.NET/Framework/v4.0.30319/mscorlib.dll
----------------------------------------
TelerikExamples
    Assembly Version: 2019.3.1022.40
    Win32 Version: 2019.3.1022.40
    CodeBase: file:///E:/Program%20Files%20(x86)/Progress/Telerik%20UI%20for%20WinForms%20R3%202019/Examples/QuickStart/bin/TelerikExamples.exe
----------------------------------------
System.Windows.Forms
    Assembly Version: 4.0.0.0
    Win32 Version: 4.7.3690.0 built by: NET472REL1LAST_C
    CodeBase: file:///C:/WINDOWS/Microsoft.Net/assembly/GAC_MSIL/System.Windows.Forms/v4.0_4.0.0.0__b77a5c561934e089/System.Windows.Forms.dll
----------------------------------------
System
    Assembly Version: 4.0.0.0
    Win32 Version: 4.7.3640.0 built by: NET472REL1LAST_C
    CodeBase: file:///C:/WINDOWS/Microsoft.Net/assembly/GAC_MSIL/System/v4.0_4.0.0.0__b77a5c561934e089/System.dll
----------------------------------------
System.Drawing
    Assembly Version: 4.0.0.0
    Win32 Version: 4.7.3190.0 built by: NET472REL1LAST_C
    CodeBase: file:///C:/WINDOWS/Microsoft.Net/assembly/GAC_MSIL/System.Drawing/v4.0_4.0.0.0__b03f5f7f11d50a3a/System.Drawing.dll
----------------------------------------
QuickStart
    Assembly Version: 2019.3.1022.40
    Win32 Version: 2019.3.1022.40
    CodeBase: file:///C:/WINDOWS/Microsoft.Net/assembly/GAC_MSIL/QuickStart/v4.0_2019.3.1022.40__5bb2a467cbec794e/QuickStart.dll
----------------------------------------
Telerik.WinControls.UI
    Assembly Version: 2019.3.1022.40
    Win32 Version: 2019.3.1022.40
    CodeBase: file:///C:/WINDOWS/Microsoft.Net/assembly/GAC_MSIL/Telerik.WinControls.UI/v4.0_2019.3.1022.40__5bb2a467cbec794e/Telerik.WinControls.UI.dll
----------------------------------------
System.Core
    Assembly Version: 4.0.0.0
    Win32 Version: 4.7.3760.0 built by: NET472REL1LAST_C
    CodeBase: file:///C:/WINDOWS/Microsoft.Net/assembly/GAC_MSIL/System.Core/v4.0_4.0.0.0__b77a5c561934e089/System.Core.dll
----------------------------------------
Telerik.WinControls
    Assembly Version: 2019.3.1022.40
    Win32 Version: 2019.3.1022.40
    CodeBase: file:///C:/WINDOWS/Microsoft.Net/assembly/GAC_MSIL/Telerik.WinControls/v4.0_2019.3.1022.40__5bb2a467cbec794e/Telerik.WinControls.dll
----------------------------------------
TelerikCommon
    Assembly Version: 2019.3.1022.40
    Win32 Version: 2019.3.1022.40
    CodeBase: file:///C:/WINDOWS/Microsoft.Net/assembly/GAC_MSIL/TelerikCommon/v4.0_2019.3.1022.40__5bb2a467cbec794e/TelerikCommon.dll
----------------------------------------
System.Xml
    Assembly Version: 4.0.0.0
    Win32 Version: 4.7.3190.0 built by: NET472REL1LAST_C
    CodeBase: file:///C:/WINDOWS/Microsoft.Net/assembly/GAC_MSIL/System.Xml/v4.0_4.0.0.0__b77a5c561934e089/System.Xml.dll
----------------------------------------
Telerik.WinControls.Themes.TelerikMetro
    Assembly Version: 2019.3.1022.40
    Win32 Version: 2019.3.1022.40
    CodeBase: file:///C:/WINDOWS/Microsoft.Net/assembly/GAC_MSIL/Telerik.WinControls.Themes.TelerikMetro/v4.0_2019.3.1022.40__5bb2a467cbec794e/Telerik.WinControls.Themes.TelerikMetro.dll
----------------------------------------
System.Configuration
    Assembly Version: 4.0.0.0
    Win32 Version: 4.7.3630.0 built by: NET472REL1LAST_B
    CodeBase: file:///C:/WINDOWS/Microsoft.Net/assembly/GAC_MSIL/System.Configuration/v4.0_4.0.0.0__b03f5f7f11d50a3a/System.Configuration.dll
----------------------------------------
Microsoft.GeneratedCode
    Assembly Version: 1.0.0.0
    Win32 Version: 4.7.3190.0 built by: NET472REL1LAST_C
    CodeBase: file:///C:/WINDOWS/Microsoft.Net/assembly/GAC_MSIL/System.Xml/v4.0_4.0.0.0__b77a5c561934e089/System.Xml.dll
----------------------------------------
Telerik.WinControls.Themes.Fluent
    Assembly Version: 2019.3.1022.40
    Win32 Version: 2019.3.1022.40
    CodeBase: file:///C:/WINDOWS/Microsoft.Net/assembly/GAC_MSIL/Telerik.WinControls.Themes.Fluent/v4.0_2019.3.1022.40__5bb2a467cbec794e/Telerik.WinControls.Themes.Fluent.dll
----------------------------------------
Telerik.WinControls.Themes.FluentDark
    Assembly Version: 2019.3.1022.40
    Win32 Version: 2019.3.1022.40
    CodeBase: file:///C:/WINDOWS/Microsoft.Net/assembly/GAC_MSIL/Telerik.WinControls.Themes.FluentDark/v4.0_2019.3.1022.40__5bb2a467cbec794e/Telerik.WinControls.Themes.FluentDark.dll
----------------------------------------
RadControlSpy
    Assembly Version: 2019.3.1022.40
    Win32 Version: 2019.3.1022.40
    CodeBase: file:///C:/WINDOWS/Microsoft.Net/assembly/GAC_MSIL/RadControlSpy/v4.0_2019.3.1022.40__5bb2a467cbec794e/RadControlSpy.dll
----------------------------------------
Telerik.WinControls.Themes.Aqua
    Assembly Version: 2019.3.1022.40
    Win32 Version: 2019.3.1022.40
    CodeBase: file:///C:/WINDOWS/Microsoft.Net/assembly/GAC_MSIL/Telerik.WinControls.Themes.Aqua/v4.0_2019.3.1022.40__5bb2a467cbec794e/Telerik.WinControls.Themes.Aqua.dll
----------------------------------------
Telerik.WinControls.Themes.Breeze
    Assembly Version: 2019.3.1022.40
    Win32 Version: 2019.3.1022.40
    CodeBase: file:///C:/WINDOWS/Microsoft.Net/assembly/GAC_MSIL/Telerik.WinControls.Themes.Breeze/v4.0_2019.3.1022.40__5bb2a467cbec794e/Telerik.WinControls.Themes.Breeze.dll
----------------------------------------
Telerik.WinControls.Themes.Desert
    Assembly Version: 2019.3.1022.40
    Win32 Version: 2019.3.1022.40
    CodeBase: file:///C:/WINDOWS/Microsoft.Net/assembly/GAC_MSIL/Telerik.WinControls.Themes.Desert/v4.0_2019.3.1022.40__5bb2a467cbec794e/Telerik.WinControls.Themes.Desert.dll
----------------------------------------
Telerik.WinControls.Themes.HighContrastBlack
    Assembly Version: 2019.3.1022.40
    Win32 Version: 2019.3.1022.40
    CodeBase: file:///C:/WINDOWS/Microsoft.Net/assembly/GAC_MSIL/Telerik.WinControls.Themes.HighContrastBlack/v4.0_2019.3.1022.40__5bb2a467cbec794e/Telerik.WinControls.Themes.HighContrastBlack.dll
----------------------------------------
Telerik.WinControls.Themes.Office2007Black
    Assembly Version: 2019.3.1022.40
    Win32 Version: 2019.3.1022.40
    CodeBase: file:///C:/WINDOWS/Microsoft.Net/assembly/GAC_MSIL/Telerik.WinControls.Themes.Office2007Black/v4.0_2019.3.1022.40__5bb2a467cbec794e/Telerik.WinControls.Themes.Office2007Black.dll
----------------------------------------
Telerik.WinControls.Themes.Office2007Silver
    Assembly Version: 2019.3.1022.40
    Win32 Version: 2019.3.1022.40
    CodeBase: file:///C:/WINDOWS/Microsoft.Net/assembly/GAC_MSIL/Telerik.WinControls.Themes.Office2007Silver/v4.0_2019.3.1022.40__5bb2a467cbec794e/Telerik.WinControls.Themes.Office2007Silver.dll
----------------------------------------
Telerik.WinControls.Themes.Office2010Black
    Assembly Version: 2019.3.1022.40
    Win32 Version: 2019.3.1022.40
    CodeBase: file:///C:/WINDOWS/Microsoft.Net/assembly/GAC_MSIL/Telerik.WinControls.Themes.Office2010Black/v4.0_2019.3.1022.40__5bb2a467cbec794e/Telerik.WinControls.Themes.Office2010Black.dll
----------------------------------------
Telerik.WinControls.Themes.Office2010Silver
    Assembly Version: 2019.3.1022.40
    Win32 Version: 2019.3.1022.40
    CodeBase: file:///C:/WINDOWS/Microsoft.Net/assembly/GAC_MSIL/Telerik.WinControls.Themes.Office2010Silver/v4.0_2019.3.1022.40__5bb2a467cbec794e/Telerik.WinControls.Themes.Office2010Silver.dll
----------------------------------------
Telerik.WinControls.Themes.Office2010Blue
    Assembly Version: 2019.3.1022.40
    Win32 Version: 2019.3.1022.40
    CodeBase: file:///C:/WINDOWS/Microsoft.Net/assembly/GAC_MSIL/Telerik.WinControls.Themes.Office2010Blue/v4.0_2019.3.1022.40__5bb2a467cbec794e/Telerik.WinControls.Themes.Office2010Blue.dll
----------------------------------------
Telerik.WinControls.Themes.Office2013Dark
    Assembly Version: 2019.3.1022.40
    Win32 Version: 2019.3.1022.40
    CodeBase: file:///C:/WINDOWS/Microsoft.Net/assembly/GAC_MSIL/Telerik.WinControls.Themes.Office2013Dark/v4.0_2019.3.1022.40__5bb2a467cbec794e/Telerik.WinControls.Themes.Office2013Dark.dll
----------------------------------------
Telerik.WinControls.Themes.Office2013Light
    Assembly Version: 2019.3.1022.40
    Win32 Version: 2019.3.1022.40
    CodeBase: file:///C:/WINDOWS/Microsoft.Net/assembly/GAC_MSIL/Telerik.WinControls.Themes.Office2013Light/v4.0_2019.3.1022.40__5bb2a467cbec794e/Telerik.WinControls.Themes.Office2013Light.dll
----------------------------------------
Telerik.WinControls.Themes.TelerikMetroBlue
    Assembly Version: 2019.3.1022.40
    Win32 Version: 2019.3.1022.40
    CodeBase: file:///C:/WINDOWS/Microsoft.Net/assembly/GAC_MSIL/Telerik.WinControls.Themes.TelerikMetroBlue/v4.0_2019.3.1022.40__5bb2a467cbec794e/Telerik.WinControls.Themes.TelerikMetroBlue.dll
----------------------------------------
Telerik.WinControls.Themes.TelerikMetroTouch
    Assembly Version: 2019.3.1022.40
    Win32 Version: 2019.3.1022.40
    CodeBase: file:///C:/WINDOWS/Microsoft.Net/assembly/GAC_MSIL/Telerik.WinControls.Themes.TelerikMetroTouch/v4.0_2019.3.1022.40__5bb2a467cbec794e/Telerik.WinControls.Themes.TelerikMetroTouch.dll
----------------------------------------
Telerik.WinControls.Themes.VisualStudio2012Dark
    Assembly Version: 2019.3.1022.40
    Win32 Version: 2019.3.1022.40
    CodeBase: file:///C:/WINDOWS/Microsoft.Net/assembly/GAC_MSIL/Telerik.WinControls.Themes.VisualStudio2012Dark/v4.0_2019.3.1022.40__5bb2a467cbec794e/Telerik.WinControls.Themes.VisualStudio2012Dark.dll
----------------------------------------
Telerik.WinControls.Themes.VisualStudio2012Light
    Assembly Version: 2019.3.1022.40
    Win32 Version: 2019.3.1022.40
    CodeBase: file:///C:/WINDOWS/Microsoft.Net/assembly/GAC_MSIL/Telerik.WinControls.Themes.VisualStudio2012Light/v4.0_2019.3.1022.40__5bb2a467cbec794e/Telerik.WinControls.Themes.VisualStudio2012Light.dll
----------------------------------------
Telerik.WinControls.Themes.Windows7
    Assembly Version: 2019.3.1022.40
    Win32 Version: 2019.3.1022.40
    CodeBase: file:///C:/WINDOWS/Microsoft.Net/assembly/GAC_MSIL/Telerik.WinControls.Themes.Windows7/v4.0_2019.3.1022.40__5bb2a467cbec794e/Telerik.WinControls.Themes.Windows7.dll
----------------------------------------
Telerik.WinControls.Themes.Windows8
    Assembly Version: 2019.3.1022.40
    Win32 Version: 2019.3.1022.40
    CodeBase: file:///C:/WINDOWS/Microsoft.Net/assembly/GAC_MSIL/Telerik.WinControls.Themes.Windows8/v4.0_2019.3.1022.40__5bb2a467cbec794e/Telerik.WinControls.Themes.Windows8.dll
----------------------------------------
Telerik.WinControls.Themes.Material
    Assembly Version: 2019.3.1022.40
    Win32 Version: 2019.3.1022.40
    CodeBase: file:///C:/WINDOWS/Microsoft.Net/assembly/GAC_MSIL/Telerik.WinControls.Themes.Material/v4.0_2019.3.1022.40__5bb2a467cbec794e/Telerik.WinControls.Themes.Material.dll
----------------------------------------
Telerik.WinControls.Themes.MaterialPink
    Assembly Version: 2019.3.1022.40
    Win32 Version: 2019.3.1022.40
    CodeBase: file:///C:/WINDOWS/Microsoft.Net/assembly/GAC_MSIL/Telerik.WinControls.Themes.MaterialPink/v4.0_2019.3.1022.40__5bb2a467cbec794e/Telerik.WinControls.Themes.MaterialPink.dll
----------------------------------------
Telerik.WinControls.Themes.MaterialTeal
    Assembly Version: 2019.3.1022.40
    Win32 Version: 2019.3.1022.40
    CodeBase: file:///C:/WINDOWS/Microsoft.Net/assembly/GAC_MSIL/Telerik.WinControls.Themes.MaterialTeal/v4.0_2019.3.1022.40__5bb2a467cbec794e/Telerik.WinControls.Themes.MaterialTeal.dll
----------------------------------------
Telerik.WinControls.Themes.MaterialBlueGrey
    Assembly Version: 2019.3.1022.40
    Win32 Version: 2019.3.1022.40
    CodeBase: file:///C:/WINDOWS/Microsoft.Net/assembly/GAC_MSIL/Telerik.WinControls.Themes.MaterialBlueGrey/v4.0_2019.3.1022.40__5bb2a467cbec794e/Telerik.WinControls.Themes.MaterialBlueGrey.dll
----------------------------------------
Telerik.WinControls.Themes.Crystal
    Assembly Version: 2019.3.1022.40
    Win32 Version: 2019.3.1022.40
    CodeBase: file:///C:/WINDOWS/Microsoft.Net/assembly/GAC_MSIL/Telerik.WinControls.Themes.Crystal/v4.0_2019.3.1022.40__5bb2a467cbec794e/Telerik.WinControls.Themes.Crystal.dll
----------------------------------------
Telerik.WinControls.Themes.CrystalDark
    Assembly Version: 2019.3.1022.40
    Win32 Version: 2019.3.1022.40
    CodeBase: file:///C:/WINDOWS/Microsoft.Net/assembly/GAC_MSIL/Telerik.WinControls.Themes.CrystalDark/v4.0_2019.3.1022.40__5bb2a467cbec794e/Telerik.WinControls.Themes.CrystalDark.dll
----------------------------------------
System.Data
    Assembly Version: 4.0.0.0
    Win32 Version: 4.7.3710.0 built by: NET472REL1LAST_C
    CodeBase: file:///C:/WINDOWS/Microsoft.Net/assembly/GAC_32/System.Data/v4.0_4.0.0.0__b77a5c561934e089/System.Data.dll
----------------------------------------
DiagramFirstLook
    Assembly Version: 1.0.0.0
    Win32 Version: 1.0.0.0
    CodeBase: file:///E:/Program%20Files%20(x86)/Progress/Telerik%20UI%20for%20WinForms%20R3%202019/Examples/Diagram/DiagramFirstLook/bin/DiagramFirstLook.exe
----------------------------------------
Telerik.WinControls.RadDiagram
    Assembly Version: 2019.3.1022.40
    Win32 Version: 2019.3.1022.40
    CodeBase: file:///C:/WINDOWS/Microsoft.Net/assembly/GAC_MSIL/Telerik.WinControls.RadDiagram/v4.0_2019.3.1022.40__5bb2a467cbec794e/Telerik.WinControls.RadDiagram.dll
----------------------------------------
Telerik.WinControls.RadDock
    Assembly Version: 2019.3.1022.40
    Win32 Version: 2019.3.1022.40
    CodeBase: file:///C:/WINDOWS/Microsoft.Net/assembly/GAC_MSIL/Telerik.WinControls.RadDock/v4.0_2019.3.1022.40__5bb2a467cbec794e/Telerik.WinControls.RadDock.dll
----------------------------------------
System.Xml.Linq
    Assembly Version: 4.0.0.0
    Win32 Version: 4.7.3190.0 built by: NET472REL1LAST_C
    CodeBase: file:///C:/WINDOWS/Microsoft.Net/assembly/GAC_MSIL/System.Xml.Linq/v4.0_4.0.0.0__b77a5c561934e089/System.Xml.Linq.dll
----------------------------------------

************** JIT Debugging **************
To enable just-in-time (JIT) debugging, the .config file for this
application or computer (machine.config) must have the
jitDebugging value set in the system.windows.forms section.
The application must also be compiled with debugging
enabled.

For example:

<configuration>
    <system.windows.forms jitDebugging="true" />
</configuration>

When JIT debugging is enabled, any unhandled exception
will be sent to the JIT debugger registered on the computer
rather than be handled by this dialog box.

***************************************************

END ERROR TEXT

***************************************************

Run the attached sample project, paste the path to the TestTemplates folder in the text box and click Start. You will notice the that the illustrated time in the labels gets bigger and bigger.

Workaround: this is not a complete solution but is reduces the load time:

radDiagram1.Clear(); 
            radDiagram1.DiagramElement.FindDescendant<Telerik.WinControls.UI.Diagrams.Primitives.BackgroundPageGrid>().FindDescendant<Telerik.WinControls.UI.Diagrams.Canvas>().Children.Clear();
		

Use attached to reproduce.

Workaround:

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: 
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. 

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.

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

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

To reproduce: 
- Add DiagramRibbonBar to a user control.
- Try setting the AssociatedControl from the smart tag.
- An error message will be shown.

Workaround:
Set it in code:
radDiagramRibbonBar1.AssociatedDiagram = radDiagram1;

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)
        {
        }

How to reproduce: check the attached video - unexpected-behavior.gif

To reproduce
- Click between the thumb and the button.

Workaround:
public class MyDiagramInputBehavior : DiagramInputBehavior
{
    public MyDiagramInputBehavior(RadDiagramElement element) : base(element)
    {


    }
    protected override bool IsScrollBar(RadElement element)
    {
        if (element != null && element is RadScrollBarElement)
        {
            return true;
        }
        return base.IsScrollBar(element);
    }
}