I've just installed 15.04 on a Lenovo Yoga 3 laptop.
Everything seems to work great out of the box except for the trackpad. The pointer is OK and left-clicks and single taps are registered, however two finger taps and two finger scrolling are not recognised. Going into the trackpad settings doesn't list two-finger taps as a selectable option. How can I enable this functionality?
This is a known issue with recent Lenovo models. The word is that the trackpad works with full functionality if you use kernel 4.0, but using 3.19 (the 15.04 kernel) requires some ad hoc workarounds. Here's a thread you might find helpful: http://www.reddit.com/r/thinkpad/comments/33gkqq/t450s_can_confirm_that_linux_kernel_4_fixes/