' Create the regions and design-time markup. Called by the designer host.
Public Overrides Function GetDesignTimeHtml(ByVal regions As DesignerRegionCollection) As String
    ' Create 3 regions: 2 clickable headers and an editable row
    regions.Add(New DesignerRegion(Me, "Header0"))
    regions.Add(New DesignerRegion(Me, "Header1"))

    ' Create an editable region and add it to the regions
    Dim editableRegion As EditableDesignerRegion = _
        New EditableDesignerRegion(Me, _
            "Content" & myControl.CurrentView, False)
    regions.Add(editableRegion)

    ' Set the highlight for the selected region
    regions(myControl.CurrentView).Highlight = True

    ' Use the base class to render the markup
    Return MyBase.GetDesignTimeHtml()
End Function

// Create the regions and design-time markup. Called by the designer host.
public override String GetDesignTimeHtml(DesignerRegionCollection regions) {
    // Create 3 regions: 2 clickable headers and an editable row
    regions.Add(new DesignerRegion(this, "Header0"));
    regions.Add(new DesignerRegion(this, "Header1"));

    // Create an editable region and add it to the regions
    EditableDesignerRegion editableRegion = 
        new EditableDesignerRegion(this, 
            "Content" + myControl.CurrentView, false);
    regions.Add(editableRegion);

    // Set the highlight for the selected region
    regions[myControl.CurrentView].Highlight = true;

    // Use the base class to render the markup
    return base.GetDesignTimeHtml();
}