Current limitation: When DiagramShapeDefaultsEditable.Connect="true", users can draw connections between shapes, but there is no event fired when a new connection is created by the user.
Requested feature: Add OnConnectionCreated event that:

• Fires when user creates a new connection by dragging from one shape to another
• Returns event arguments containing:
  • FromShapeId — the source shape identifier
  • ToShapeId — the target shape identifier
  • Connection — reference to the newly created connection object (or its properties)
• Allows developers to intercept, validate, or customize the connection before it's finalized

Use case: We need to capture user-created connections to persist them to database, validate business rules (e.g., prevent circular dependencies), and set connection properties (type, label, color) based on context.

Current limitation: The Diagram component does not provide native context menu integration. There are no events like OnShapeContextMenu or OnConnectionContextMenu that fire on right-click. Developers cannot show contextual actions (edit, delete, copy, connect) when user right-clicks on diagram elements.

Requested feature: Add context menu support for Diagram elements:

1. Context menu events:
   • OnShapeContextMenu — fires on right-click on a shape
   • OnConnectionContextMenu — fires on right-click on a connection
   • OnCanvasContextMenu — fires on right-click on empty canvas area (for "paste", "add shape" actions)
2. Event arguments:
   • DiagramShapeContextMenuEventArgs:
     • ShapeId — the clicked shape identifier
     • ClientX, ClientY — mouse position for menu placement
     • PageX, PageY — page coordinates
   • DiagramConnectionContextMenuEventArgs:
     • ConnectionId — the clicked connection identifier
     • FromShapeId, ToShapeId — connected shape identifiers
     • ClientX, ClientY, PageX, PageY
   • DiagramCanvasContextMenuEventArgs:
     • ClientX, ClientY, PageX, PageY
     • DiagramX, DiagramY — coordinates in diagram space (for placing new shapes)
3. Integration with TelerikContextMenu:
   • Ability to bind TelerikContextMenu to diagram and show it on right-click events
   • Automatic prevention of browser default context menu

Use case:
In workflow/process diagram editors, context menu is essential for:

• Shape actions: Edit, Delete, Duplicate, Copy/Paste, Change type, View details
• Connection actions: Edit transition, Delete, Change routing
• Canvas actions: Paste, Add new shape at cursor position, Zoom controls
• Conditional actions: Show different menu items based on shape type or state

Currently, there is no way to detect right-click on specific diagram elements. The only workaround is complex JavaScript interop to attach event listeners to SVG elements, which is fragile and breaks on re-render.

Example of desired API:

<TelerikDiagram @ref="@DiagramRef"
                OnShapeContextMenu="@OnShapeRightClick"
                OnConnectionContextMenu="@OnConnectionRightClick"
                OnCanvasContextMenu="@OnCanvasRightClick">
    <DiagramShapes>
        @foreach (var shape in Shapes)
        {
            <DiagramShape Id="@shape.Id">
                <DiagramShapeContent Text="@shape.Name" />
            </DiagramShape>
        }
    </DiagramShapes>
</TelerikDiagram>

<TelerikContextMenu @ref="@ShapeContextMenu" 
                    Data="@ShapeMenuItems"
                    OnClick="@OnShapeMenuClick">
    <ItemTemplate Context="item">
        <TelerikFontIcon Icon="@item.Icon" />
        <span>@item.Text</span>
    </ItemTemplate>
</TelerikContextMenu>

@code {
    private TelerikContextMenu<MenuItem>? ShapeContextMenu;
    private string? ClickedShapeId;
    
    private async Task OnShapeRightClick(DiagramShapeContextMenuEventArgs args)
    {
        ClickedShapeId = args.ShapeId;
        await ShapeContextMenu.ShowAsync(args.ClientX, args.ClientY);
    }
    
    private async Task OnShapeMenuClick(MenuItem item)
    {
        switch (item.Action)
        {
            case "edit":
                await OpenShapeEditor(ClickedShapeId);
                break;
            case "delete":
                await DeleteShape(ClickedShapeId);
                break;
            case "duplicate":
                await DuplicateShape(ClickedShapeId);
                break;
        }
    }
}

We would like to use built-in tooltips for Shapes an Connections in the Diagram component to show some additional information of the different items and their relation.

Would it be possible to add this functionality similar to the MapLayerMarkerSettingsTooltip of the Map component?

Current limitation: The Diagram component only provides OnShapeClick event. There is no native double-click event for shapes.
Requested feature: Add OnShapeDoubleClick event that:

• Fires when user double-clicks on a shape
• Returns DiagramShapeDoubleClickEventArgs containing the shape Id (similar to DiagramShapeClickEventArgs)
• Allows developers to differentiate between selection (single-click) and action (double-click)

Use case: In workflow editors, single-click should select a shape, while double-click should open an editor dialog. Currently, we have to implement manual timing-based detection which is unreliable and doesn't match native OS double-click behavior.

Expose an OnShapeDrop event for the Diagram. It should provide information about the shape's current X and Y coordinates.

This would allow the user to save the diagram (e.g., as json) and load it later. 

Current limitation: The Diagram component only allows zoom through mouse interactions (scroll wheel). The Zoom parameter sets only the initial zoom level and cannot be changed at runtime. There are no methods to programmatically control the viewport.

Requested feature: Add programmatic viewport control API:

1. Two-way Zoom binding:
   @bind-Zoom support with ZoomChanged event
   Event args containing OldZoom and NewZoom values
2. Viewport control methods on TelerikDiagram reference:
   SetZoomAsync(double level) — set zoom to specific level
   ZoomInAsync(double? step) — zoom in by step (default: ZoomRate)
   ZoomOutAsync(double? step) — zoom out by step
   ResetZoomAsync() — reset to initial Zoom value (100%)
   BringIntoViewAsync(IEnumerable<string> shapeIds) — pan/zoom to show specific shapes
   FitToScreenAsync() — auto-zoom to fit all shapes in viewport

Use case:
In enterprise workflow/process editors, users need navigation controls beyond mouse wheel:
Accessibility: Users with trackpads, touch screens, or motor impairments cannot easily use scroll wheel zoom
Toolbar buttons: Standard diagram tools (Visio, Draw.io, Lucidchart) provide +/−/100%/Fit buttons
Programmatic navigation: After adding a new shape, auto-scroll to show it; on search result, navigate to found shape
Keyboard shortcuts: Implement Ctrl+Plus/Minus for zoom without native support

<TelerikDiagram @ref="@DiagramRef"
                @bind-Zoom="@CurrentZoom"
                ZoomChanged="@OnZoomChanged">
    ...
</TelerikDiagram>

<TelerikButton OnClick="@(() => DiagramRef.ZoomInAsync())">+</TelerikButton>
<TelerikButton OnClick="@(() => DiagramRef.ZoomOutAsync())">−</TelerikButton>
<TelerikButton OnClick="@(() => DiagramRef.SetZoomAsync(1.0))">100%</TelerikButton>
<TelerikButton OnClick="@(() => DiagramRef.FitToScreenAsync())">Fit</TelerikButton>

@code {
    private TelerikDiagram? DiagramRef;
    private double CurrentZoom = 1.0;
    
    private async Task NavigateToShape(string shapeId)
    {
        await DiagramRef.BringIntoViewAsync(new[] { shapeId });
    }
}

Current limitation: DiagramConnectionType only supports Cascading (orthogonal) and Polyline types. There is no curved or Bezier option.
Requested feature: Add a new connection type such as DiagramConnectionType.Bezier or DiagramConnectionType.Curved that:

• Renders smooth curved lines between shapes
• Provides natural-looking connections for complex diagrams
• Optionally allows control point customization

Use case: For workflow diagrams with many crossing connections, curved lines improve visual clarity and reduce cognitive load compared to sharp 90° angles.

When there is no predefined Diagram layout, and a shape parameter value changes at runtime:

• If there are no connections, all shape positions are reset and the shapes display in a single row.
• If there are connections, the overall layout persists, but all shape positions change.

Possible workarounds:

• Recreate the whole Diagram as in the test page below.
• Remove the shapes from the Diagram declaration and use the JSON state, similar to this KB article: https://blazorrepl.telerik.com/QUYFmtbY15a2ypLw58

To reproduce:

<label class="lbl">
    Width: <TelerikNumericTextBox @bind-Value="@SelectedShapeWidth" Width="120px" />
</label>

<label class="lbl">
    Height: <TelerikNumericTextBox @bind-Value="@SelectedShapeHeight" Width="120px" />
</label>

<label class="lbl">
    X: <TelerikNumericTextBox @bind-Value="@SelectedShapeX" Width="120px" />
</label>

<label class="lbl">
    Y: <TelerikNumericTextBox @bind-Value="@SelectedShapeY" Width="120px" />
</label>

<label class="lbl">
    Angle: <TelerikNumericTextBox @bind-Value="@SelectedShapeAngle" Width="120px" />
</label>

<style>
    .lbl {
        display: block;
        margin: 0 0 1em;
    }
</style>

<TelerikButton OnClick="@OnButtonClick">Apply</TelerikButton>

@if (RenderDiagram)
{
    <TelerikDiagram Height="300px" Zoom="0.8">
        <DiagramShapes>
                <DiagramShape
                            Id="shape1"
                            Width="100"
                            Height="100"
                            X="200"
                            Y="50">
                    <DiagramShapeContent Text="Shape 1" />
                    <DiagramShapeRotation Angle="0" />
                </DiagramShape>
                <DiagramShape
                            Id="@SelectedShapeId"
                            Width="@SelectedShapeWidth"
                            Height="@SelectedShapeHeight"
                            X="@SelectedShapeX"
                            Y="@SelectedShapeY">
                    <DiagramShapeContent Text="Shape 2" />
                    <DiagramShapeRotation Angle="@SelectedShapeAngle" />
                </DiagramShape>
        </DiagramShapes>
    </TelerikDiagram>

    <TelerikDiagram Height="300px" Zoom="0.8">
        <DiagramShapes>
                <DiagramShape
                            Id="shape1"
                            Width="100"
                            Height="100"
                            X="200"
                            Y="50">
                    <DiagramShapeContent Text="Shape 1" />
                    <DiagramShapeRotation Angle="0" />
                </DiagramShape>
                <DiagramShape
                            Id="@SelectedShapeId"
                            Width="@SelectedShapeWidth"
                            Height="@SelectedShapeHeight"
                            X="@SelectedShapeX"
                            Y="@SelectedShapeY">
                    <DiagramShapeContent Text="Shape 2" />
                    <DiagramShapeRotation Angle="@SelectedShapeAngle" />
                </DiagramShape>
        </DiagramShapes>
        <DiagramConnections>
            <DiagramConnection FromId="shape1" ToId="shape2" />
        </DiagramConnections>
    </TelerikDiagram>
}

@code {
    #nullable enable

    private List<ShapeDescriptor> DiagramShapeList { get; set; } = new();

    private string SelectedShapeId { get; set; } = "shape2";
    private double? SelectedShapeAngle { get; set; } = 0;
    private double? SelectedShapeWidth { get; set; } = 100;
    private double? SelectedShapeHeight { get; set; } = 100;
    private double? SelectedShapeX { get; set; } = 300;
    private double? SelectedShapeY { get; set; } = 200;

    private bool RenderDiagram { get; set; } = true;

    private async Task OnButtonClick()
    {
        if (string.IsNullOrEmpty(SelectedShapeId))
        {
            return;
        }

        RenderDiagram = false;
        await Task.Delay(1);

        RenderDiagram = true;
    }

    public class ShapeDescriptor
    {
        public string Id { get; set; } = string.Empty;
        public string ParentId { get; set; } = string.Empty;
        public DiagramShapeType Type { get; set; } = DiagramShapeType.Image;
        public string Text { get; set; } = string.Empty;
        public string Source { get; set; } = string.Empty;
        public double? Width { get; set; } = 100;
        public double? Height { get; set; } = 100;
        public double? X { get; set; }
        public double? Y { get; set; }
        public double? Angle { get; set; }
    }
}

Current limitation: The Diagram component only allows pan through mouse interactions (Ctrl+drag). There are no methods to programmatically control the viewport.

Requested feature: Add programmatic viewport control API:

1. PanToAsync(double x, double y) — pan viewport to specific coordinates
   PanByAsync(double deltaX, double deltaY) — pan viewport by offset
   BringIntoViewAsync(IEnumerable<string> shapeIds) — pan/zoom to show specific shapes
   FitToScreenAsync() — auto-zoom to fit all shapes in viewport
2. Pan position binding (optional):
   @bind-PanX / @bind-PanY or PanChanged event
   

Use case:
Programmatic navigation: After adding a new shape, auto-scroll to show it; on search result, navigate to found shape

===

Forked from https://feedback.telerik.com/blazor/1708938