I had been operating under the assumption that any time I worked on a set of tracks, they were shown by a file in the bottom pane.
For example, when I create a trail network, an automatic new file is created with tracks and waypoints. I was assuming that joined tracks, but joined. Instead, the new "file" is invisible, until right-click>>save.
Another suggestion to make the program more consistent would be when you join tracks, automatically create a "joined tracks layer."
Sorry, I'm looking at this with outside eyes and putting suggestions in the help forum to try to make it easier, rather than in the suggestion forum.