/// <summary>
/// Attach the control to a specified document's control collection using a specified process.
/// </summary>
/// <param name="collection">The control collection to hold the control.</param>
/// <param name="range">The location of the control.</param>
/// <param name="width">The width of the control.</param>
/// <param name="height">The height of the control.</param>
/// <param name="shape">The control's inline shape object in the document</param>
/// <returns>The component of the attached control.</returns>
protected override Control Attach(ControlCollection collection, Word.Range range, float width, float height, out Word.InlineShape shape)
{
//adds a rich text box control to the document
var control = collection.AddRichTextBox(range, width, height, ObjectId);
//initialize control properties
control.ReadOnly = true;
control.BackColor = Color.White;
shape = control.InlineShape;
return(control);
}