When you try editing the network in the vista, the first network you created always comes up. This can be difficult in drawings when there are 3 or more pipe networks.
I still haven't figured out how to do it when you first open the drawing and go to edit the network for the first time. However, after you open the panorama close it immediately and then closed the pipe network toolbar. Then click edit network again and click on pipe panorama. When the window opens up, it will be on the correct pipe network to correct.
The key is to always close the pipe network panorama before you close the edit network toolbar.