Otis,
Try this
1) right click on x-ray and add to favorites
2) change the drop down from "all transitions" to "my favorites"
3) you should see only the x-ray in "my favorites" remove all others if you added some before
4) on the library menu icon, icon to the right my favorites, left click and "apply random transition to all"
You should have x-ray transition applied to all photo's
Jeff