After upgrading to Yosemite and FCPX as well, the timeline functions have changed. There is no longer a timeline 'library' (if that's what you want to call it) and the icon/button to switch to it is gone. I cannot find my older projects (after FCPX 'upgraded' the libraries) timelines. I managed to get one of them by accident, but that's the only one.
****Yosemite Broke My Mac*******
