I have a view that works fine to display rendering parameters for a title and body of a widget, however, I've added a checkbox field to the rendering items for that template and when I try to use it in the view to check it seems to give me a null reference exception.  I've tried checking to see if RenderingContext.Current.Rendering.Parameters["Expandable"] is equal to "0" or "false" but this fails regardless of whether the checkbox is checked or not and when I try to display RenderingContext.Current.Rendering.Parameters["Expandable"] as part of the body of the widget it throws a null reference exception.  What am I doing wrong?  How do I retrieve the value of such a rendering parameter within the view??