Dynamic Connector drawn programatically requries manual refresh?

[Dr. 9]

Using ActiveXControl on a C# .NET winform.

I have a skeleton code drawing a few shapes and connecting with the "Dynamic
Connector" the lines route around shapes - good.

When using this routine en mass to draw many shapes (say 100) and saving the
visio I'm getting a .vsd file where the dynamic connectors are all in the
middle of the diagram - only if I manually double click them do they 'spring'
to where they should be.

I have tried using the ActiveX control's refresh, inserting a thread.wait,
and an Application.DoEvents() with no success.

Manually I've found that if I SelectAll and RotateLeft RotateRight - they'll
co-operate.

What gives? Is there a COM method to 'flush' or whatever I need here?