using System;
using System.Windows.Forms;
using System.Drawing.Design;
using DevExpress.XtraReports.UserDesigner;
// ...

private void button1_Click(object sender, EventArgs e) {
    // Create a new End-User Designer.
    XRDesignForm designForm = new XRDesignForm();

    // Handle the DesignPanelLoaded event.
    designForm.DesignMdiController.DesignPanelLoaded +=
        new DesignerLoadedEventHandler(DesignMdiController_DesignPanelLoaded);

    // Load the report into the designer. 
    designForm.OpenReport(new XtraReport1());

    // Show the End-User Designer window.
    designForm.Show();
}

private void DesignMdiController_DesignPanelLoaded(object sender, DesignerLoadedEventArgs e) {
    // Get the toolbox service.
    IToolboxService ts = (IToolboxService)e.DesignerHost.GetService(typeof(IToolboxService));

    // Get a collection of toolbox items.
    ToolboxItemCollection coll = ts.GetToolboxItems();

    // Iterate through toolbox items.
    foreach (ToolboxItem item in coll) {
        // Add the "Cool" prefix to all toolbox item names.
        item.DisplayName = "Cool " + item.DisplayName;
    }
}

Imports System
Imports System.Windows.Forms
Imports System.Drawing.Design
Imports DevExpress.XtraReports.UserDesigner
' ...

Private Sub button1_Click(ByVal sender As Object, ByVal e As EventArgs) Handles button1.Click
    ' Create a new End-User Designer.
    Dim designForm As New XRDesignForm()

    ' Handle the DesignPanelLoaded event.
    AddHandler designForm.DesignMdiController.DesignPanelLoaded, _ 
        AddressOf DesignMdiController_DesignPanelLoaded

    ' Load the report into the designer. 
    designForm.OpenReport(New XtraReport1())

    ' Show the End-User Designer window.
    designForm.Show()
End Sub

Private Sub DesignMdiController_DesignPanelLoaded(ByVal sender As Object, _ 
ByVal e As DesignerLoadedEventArgs)
    ' Get the toolbox service.
    Dim ts As IToolboxService = _ 
        CType(e.DesignerHost.GetService(GetType(IToolboxService)), IToolboxService)

    ' Get a collection of toolbox items.
    Dim coll As ToolboxItemCollection = ts.GetToolboxItems()

    ' Iterate through toolbox items.
    For Each item As ToolboxItem In coll
        ' Add the "Cool" prefix to all toolbox item names.
        item.DisplayName = "Cool " & item.DisplayName
    Next item
End Sub