The interface is the same. The timeline did not go away. Try resetting your workspace. Show us a screen shot of the problem. Composition in and out points are set with the composition settings or by trimming the comp to the work area set in the timeline. You could have also hidden columns in the timeline but I'm not sure because I can not see what you are seeing.
Thanks for your thoughts. Perhaps I was not clear. If I remember correctly, in CS5.5 I could double-click a composition to preview it and there would be a timeline beneath it so that I could scrub up and down and set the in/out points. I have reset my Standard Workspace and there is no timeline beneath a Composition when previewed. There is, however, for a Footage item.
Composition Settings only lets me adjust the Start Frame and Duration. I don't want to make a global change to the composition, simply set an in and out point for the composition's use when placed within another composition.
There have been no such changes in that area of the user itnerface. Show us a screenshot of what you're seeing.
I have finally solved it. I simply need to drag my MasterComp into Comp01 and then alt-double-click MasterComp to preview the Layer, or right-click and select Open Layer. Now I can set the in and out points.