Hello. I have a couple questions regarding new elements not being displayed on InfoSWMM.

I have an large existing infoSWMM model created by somebody else in which I need to add parallel pipes to run different scenarios. I am able to draw these elements, run new scenarios, and obtain results. When the file is opened the next day these elements are not being displayed but they are still listed in their attribute tables. I found a way around this issue which is to draw an additional pipe and manhole for the previously added items to show up.

Is there a reason why these elements disappear? And how does drawing additional items makes them appear? Thank you for your help.