Issue about graphic output with the kernel 3.8.3

After updating the kernel to last version (3.8.3-201.fc18) and booting into it, my laptop detects a "ghost" screen on VGA port. My main screen is LVDS1 1366x768, but from the login screen, the desktop output becomes 1024x768. I found in System Settings that there is an VGA1 screen 1024x768 (VGA port is empty :( ) and the LVDS1 is set to 1024x768. Now I have to reset to normal size each time I boot into my laptop.
Information:
Fedora 18 KDE
Dell Inspiron 1440, graphic chipset Intel GMA 4500
Thank for help :)