How To Remove The White Dots (Draw Grid) Using Ubuntu Tweak On Ubuntu 12.10
Here is a guide to remove the white dots from the LightDm login screen using Ubuntu Tweak. If you don’t have Ubuntu Tweak installed on your system read this article and install Ubuntu Tweak. It’s also possible to change the Gtk theme, the icon theme, the background, remove/change the Ubuntu logo and to disable the login sound and the guest account.
To start Ubuntu Tweak press the SuperKey and type: ubuntu tweak. When Ubuntu Tweak is started click on the following buttons: Tweaks -> Login Settings click on the Unlock button and enter your password. Then click on the turn off draw grid button. Now the white dots are removed from the login screen.
To disable the Guest account you need click on the Guest account button and it will be disabled.
To diable the Play login sound option just click on the button.
If you have other Gtk themes or icon themes installed and you want to use them, click on the Gtk theme and the icon theme buttons and select the themes you want to use.
To change the logo or background click on the images and browse to the folder where you have the images stored. Select the image you want to use and click on the Open button.
When you have made the changes close Ubuntu Tweak and logout to see you customized login screen.
Please note that changing the login background image doesn’t work that you can fix this by using the same image as your desktop background.