after d&d, master shape displays as a rectangle in viewer

[Pierre]

Hello.

I'm flumoxed, as after I d&d a newly created master shape from my
'favorites' stencil container to the visio viewer window, the master shape
appears (or is displayed) as a simple rectangle. I thought there would be
some sort of layer-visibility of attribute protection issue related to the
shape, but none of the above applies? Curiously, the said master shape can
always be edited (edit master shape) and saved without any issues, and all my
other master shapes do not exhibit the same problem?

Any ideas?
Thanks!
P.