[DllImport("user32.dll")]
private static extern IntPtr SendMessage(HandleRef hWnd, uint Msg, IntPtr wParam, IntPtr lParam);

///////////////////////////////////////////////////////////////////////
/// <summary>
///     Enables the elevated shield icon on the given button control
/// </summary>
/// <param name="ThisButton">
///     Button control to enable the elevated shield icon on.
/// </param>
///////////////////////////////////////////////////////////////////////
private void EnableElevateIcon_BCM_SETSHIELD(Button ThisButton)
{
	// Input validation, validate that ThisControl is not null
	if (ThisButton == null)
	{
		return;
	}

	// Define BCM_SETSHIELD locally, declared originally in Commctrl.h
	uint BCM_SETSHIELD = 0x0000160C;

	// Set button style to the system style
	ThisButton.FlatStyle = FlatStyle.System;

	// Send the BCM_SETSHIELD message to the button control
	SendMessage(new HandleRef(ThisButton, ThisButton.Handle), 
		BCM_SETSHIELD, new IntPtr(0), new IntPtr(1));
}