RadDiagram does not render stroke thinner than 2px.

Code to reproduce:

        <telerik:RadDiagram ID="webDiagram" runat="server">
            <ShapesCollection>
                <telerik:DiagramShape Id="s1">
                    <StrokeSettings Width="1" Color="grey" />
                </telerik:DiagramShape>
            </ShapesCollection>
        </telerik:RadDiagram>

Actual result:

Expected result:

When you use the ConnectionDataSource of RadDiagram to data bind an SqlDataSource to its connections, a NullReferenceException is thrown.

You can avoid this issue by using ConnectionDataSourceId instead.

A connector that is only connected to one shape cannot be imported via JSON.
Tested here:
http://demos.telerik.com/aspnet-ajax/diagram/examples/saveload/defaultcs.aspx

JSON:
{
    "shapes": [{
        "id": "nadal_winner",
        "background": "#f18100",
        "hover": {
            "opacity": 0.2
        },
        "cursor": "pointer",
        "content": {
            "align": "center middle",
            "text": "R. Nadal",
            "color": "#fff"
        },
        "selectable": true,
        "serializable": true,
        "enable": true,
        "type": "rectangle",
        "path": "",
        "visual": null,
        "x": 180,
        "y": 155,
        "minWidth": 20,
        "minHeight": 20,
        "width": 140,
        "height": 30,
        "connectors": [{
            "name": "Top",
            "description": "Top Connector"
        }, {
            "name": "Right",
            "description": "Right Connector"
        }, {
            "name": "Bottom",
            "description": "Bottom Connector"
        }, {
            "name": "Left",
            "Description": "Left Connector"
        }, {
            "name": "Auto",
            "Description": "Auto Connector"
        }],
        "rotation": {
            "angle": 0
        },
        "stroke": {
            "width": 0,
            "color": "#fff"
        },
        "connectorDefaults": {
            "background": "#444444",
            "stroke": {
                "color": "white"
            },
            "hover": {
                "background": "white",
                "stroke": {
                    "color": "#444444"
                }
            }
        },
        "undoable": false
    }],
    "connections": [{
        "from": {
            "shapeId": "nadal_winner",
            "connector": "Right"
        },
        "to": "OK6oDroWug",
        "id": "OK6oDroWug",
        "background": "Green",
        "hover": {
            "stroke": {}
        },
        "cursor": "pointer",
        "content": {
            "align": "center middle",
            "text": "",
            "color": "#444444"
        },
        "selectable": true,
        "serializable": true,
        "enable": true,
        "startCap": "none",
        "endCap": "none",
        "points": [],
        "stroke": {
            "width": 2,
            "color": "#6c6c6c"
        },
        "select": {
            "handles": {
                "width": 8,
                "height": 8,
                "background": "white",
                "stroke": {
                    "color": "#444444"
                }
            }
        }
    }]
}

Does not matter what value is set to the Connection's StartCap/EndCap properties, the ends of the connection are rendered as if the value of these properties is "None".

The connection StartCap and EndCap values are not applied when set through ConnectionDefaults.
The bug is introcuded version 2016 R3 SP1


Code to reproduce the probelem:
        <telerik:RadDiagram ID="RadDiagram2" runat="server" Skin="Windows7" Height="365" Width="1600">
            <ShapeDefaultsSettings Height="30" Width="100">
                <ContentSettings FontSize="12" />
                <FillSettings Color="#f2f2f2" />
                <StrokeSettings Width="2" />
            </ShapeDefaultsSettings>
            <LayoutSettings Enabled="true" ></LayoutSettings>
            <ShapesCollection>
                <telerik:DiagramShape Id="s1"></telerik:DiagramShape>
                <telerik:DiagramShape Id="s2"></telerik:DiagramShape>
                <telerik:DiagramShape Id="s3"></telerik:DiagramShape>
            </ShapesCollection>
            <ConnectionsCollection>
                <telerik:DiagramConnection>
                    <FromSettings ShapeId="s1" />
                    <ToSettings ShapeId="s2" />
                </telerik:DiagramConnection>
                <telerik:DiagramConnection>
                    <FromSettings ShapeId="s2" />
                    <ToSettings ShapeId="s3" />
                </telerik:DiagramConnection>
            </ConnectionsCollection>
            <ConnectionDefaultsSettings StartCap="FilledCircle" EndCap="ArrowEnd" />
        </telerik:RadDiagram>

When more than one shapes have HTML content containing image with the same path, only the image inside the first shape is rendered:
https://www.screencast.com/t/mYJVfSOlP


Code to reproduce:
        <telerik:RadDiagram runat="server" ID="RadDiagram1">
            <LayoutSettings Enabled="true" Type="Tree" Subtype="Right" />
            <ShapesCollection>
                <telerik:DiagramShape Id="s1" >
                    <ContentSettings Html="<div>Shape 1</div><img src='sampleImage.png' />" />
                </telerik:DiagramShape>
                 <telerik:DiagramShape Id="s2" >
                    <ContentSettings Html="<div>Shape 2</div><img src='sampleImage.png' />" />
                </telerik:DiagramShape>
            </ShapesCollection>
        </telerik:RadDiagram>

When you change the beginning or the end of an existing RadDiagram connection and call the client-side save() method, the exported data for the modified connection will not be updated.

RadDiagram throws a NullReferenceException when you bind it declaratively and place it in the ItemTemplate of a data bound control, for example a Repeater.