I've did a quick test with 3 greeters in Xubuntu 15.04. The results are the following:
* unity-greeter: timed autologin works always
* lightdm-gtk-greeter: timed autologin fails if configured user is currently selected in user list at the moment timeout expires, but it does work otherwise.
* lightdm-kde-greeter: timed autologin doesn't work at all
So, this bug is much more likely to be related to the greeters than to lightdm itself. However, what I did is a "dirty" test (all greeters installed in a same Ubuntu flavour), so I may have introduced some misconfiguration that may lead to the problems related here. A more reliable result may require that each greeter be tested on its proper Ubuntu flavour with default settings (i.e. Ubuntu with unity-greeter, Kubuntu with lightdm-kde-greeter, etc.).
I've did a quick test with 3 greeters in Xubuntu 15.04. The results are the following:
* unity-greeter: timed autologin works always
* lightdm- gtk-greeter: timed autologin fails if configured user is currently selected in user list at the moment timeout expires, but it does work otherwise.
* lightdm- kde-greeter: timed autologin doesn't work at all
So, this bug is much more likely to be related to the greeters than to lightdm itself. However, what I did is a "dirty" test (all greeters installed in a same Ubuntu flavour), so I may have introduced some misconfiguration that may lead to the problems related here. A more reliable result may require that each greeter be tested on its proper Ubuntu flavour with default settings (i.e. Ubuntu with unity-greeter, Kubuntu with lightdm- kde-greeter, etc.).