you can press the shift key, but with the latest driver this workaround doesn't work anymore. Highlight parts of formulas in Numbers doesn't work. after log in, Wacom doesn't work for a couple of seconds. This might be a hardware issue and totally unrelated, but it made troubleshooting and fixing this problem especially difficult. installed latest driver, log in screen, Wacom doesn't work.
I had to unplug and replub the USB-to-ethernet, run dhclient, then apt-get install nvidia-346 to get about 5% of the update before networking failed.
Now on a restart it fails to make it to the login prompt. I just updated my laptop from Ubuntu 14.10 to Ubuntu 15.04.