I have shapes that I like to use as containers, but I don't know how to specify to visio that these shapes are containers. I assume this property is somewhere in the shapesheet. I would rather not get into vba code for this unless someone has ready-made code to do something.
I find visios container options to be a bit bland and in some cases it is hard to control aspects such as the background color or bevel.
Very simple, open the shape's shapesheet editor,
add section User-defined cells (it may already be there ... )
add row to this section
User.msvStructureType
and set it to
="Container"
Job done.