I was affected as well but after I upgraded with the software from xorg-edgers PPA, and I selected lightdm again, the problem has gone.
So I think that this isn't a problem of lightdm rather it's a problem of xorg related software.
If you want to upgrade too, you should refer to https://launchpad.net/~xorg-edgers/+archive/ppa
I was affected as well but after I upgraded with the software from xorg-edgers PPA, and I selected lightdm again, the problem has gone.
So I think that this isn't a problem of lightdm rather it's a problem of xorg related software.
If you want to upgrade too, you should refer to https:/ /launchpad. net/~xorg- edgers/ +archive/ ppa