KDE overrides lightdm logon screen [duplicate]

I accidently solved one part of one of my questions.

To fix login screen problem (lightDM): At first it may not be overridden and just switched to kdm. Enter this command in terminal:

sudo dpkg-reconfigure lightdm

Hit enter to enter the menu. Select light-dm or gdm instead of kdm and hit enter again. logout or reboot to see if it's fixed.

If the problem persists it means that kde changed the theme of lightdm. Enter this command in terminal: sudo gedit /etc/lightdm/lightdm.conf and change/add these lines:

greeter-session=unity-greeter
user-session=ubuntu

save the file, sudo reboot, enjoy!