I am running 12.04 LTS, fully updated. My system is configured to automatically log me in into my account. Auto-login works fine.
However, sometimes I need to access the unity-greeter/lightdm login screen. For example, this happens when I log out and then want another user want to log into their account. The interface we get is exactly the one shown on the Wikipedia page for LightDM:
- the password prompt is grayed out and I am unable to type my password
- the mouse moves fine but I cannot click the system icons on the top-right corner of the menu bar does not work
- I can switch using ctrl-alt-f? to a console and login fine using the text/console login prompt. If I kill X, I am again returned to the same unusable login screen.
How can I fix this? How can a user log into their graphical environment without having to reboot the system?