Inserting shape splits connector

[philippec]

I have been experimenting with it a bit.  The Insert mode doesn't have an influence as in MS Word. 
The shape at the right moves to the right when there is no place to insert the third  shape between the two shapes.
This is with Flowcharts.  But not all shapes are created equal, especially my electrical symbols.

In Visio 2010, I haven't found where to change the splitAllow property.  I don't want to do it in the Shapesheet.
And how do I implement the Flowchart behaviour for my Edisons ?

[philippec]

Here I am working with Visio 2003.
I had a look at "Developing Visio Solutions"
http://msdn.microsoft.com/en-us/library/aa201732(office.10).aspx
There it is called "Plow every shape"
In menu File, Page setup,Layout and Routing, Other, I find "Move other shapes away on drop" and "Enable Connector Splitting.  The shapesheet settings override this.  I have noticed that the shaepsheet settings are not preserved when copying a shape.  So I made a new master shape.
But  the shape won't move in my drawing.

See the attachment.