I have also had problems with Yosemite and Latex. Besides frequent crashes upon typesetting, I also found the following bug: If I invoke Zoom, either with a key command or by clicking on the green button in the upper left corner of a window, Mission Control awakens and moves the window onto a different level. The menu bar disappears, too. I disabled Mission Control ages ago, and never use it. I disabled it again via the terminal after installing Yosemite. But this "ghost" connection remains. I can enlarge a window by manually dragging a corner without encountering this bug.
Jenny