is there a difference between how revit 2017 handles beam systems

I have a beam system in place but I can not select any of the joists in the system unless I remove the system. I can not select them in plan or in section. I tried starting a new project to see if there was something weird about the project since I took it over from a former employee. I opened 2015 to see if maybe it was something I was doing and had no problem selecting a beam with the system intact. Is there a setting I might have inadvertently changed? I also have a hard time hiding items in a linked architectural model.

It sounds like you may have the Select option "Select Pinned Elements" disabled. That feature would make it impossible to select the beams in the system since they are a pinned element, pinned to the host beam system. There are two kind of pin behaviors, those we use the Pin Element tool on and those that are part of system families such as Curtain Panels, Grids and Mullions...and...Beam System beams.

The Modify button on the ribbon has a small Select drop down under it and there are Icons for those options at the bottom right corner of the UI.