I can't get module dependencies to persist

I have a Scala program that is dependent on scala.xml, so I have to add a module dependency, which I'm doing via Ctrl-Alt-Shift-S and adding the relevant module. Everything works fine, but if I close IntellijIDEA and open it again, it has forgotten the module I've added and I have to add it again. How do I get the module to stay added? (Note that I'm not using any dependency manager such as Maven or SBT - this should be too simple a project to merit one.)

评论操作 固定链接

Similar problem here. In my case, I have to set the scope of  a dependency every time