I'm having an issue with the implicitplot3d command in Maple 16.  The sequence of commands I've listed below works just fine in Maple 15, but in Maple 16 I'm getting a problem.  Sometimes no graph will display;  other times, Maple may initially graph the surface correctly, but as soon as I rotate the graph, the surface disappears.  Furthermore, the following strange things happen:

1) Re-executing the command after rotating does not redraw the image ...

I'm trying to get Maple to shade the approximating rectangles in a Riemann Sum but am having no luck -- any help would be appreciated.  Curretnly I've typed the following:

RiemannSum( x^2+1,x=0..2, boxoptions = [filled = true] );

Doesn't seem to want to shade the area.  Changing other boxoptions (e.g. color, etc.) does have an effect -- it's just the shading that is not working.

Thanks in advance,

-Greg