I have created a few pipe fitting families recently and they act differently when editing a connected pipe. Some fittings will resize based on the connected pipe and some will not.

What is the trick(s) to insuring the fitting size can be influenced by a connected pipe?

ps - The fittings that are working were copies of the ones that do not. For example... Wye 45 Single (which works) was made from a Wye 45 Double.

Thanks!