Custom Properties

I'm attempting to build my Template Library with custom properties. In my case, I need custom properties to be specific to certain takeoff items rather than "all liner", "all area", etc... So I create my Custom Property with the "Hidden By Default" option selected. I can then go into all of my takeoff templates and select which custom properties I want to use in that template, using the gear icon at the top right of the window. The problem is, this doesn't save the custom property to the takeoff template. Rather, it looks like I need to use that gear icon every time I want to use the custom property in a certain takeoff template. I'm not sure if this was by design or not, but it would be nice to have the properties save to the template item.