When connecting the Inspirion 1505 to an external monitor, I press Fn+F8 to cycle the display to the external monitor. Then, when I press Fn+F8 again to display the GNOME window manager on the laptop screen, it is displayed only in half of the laptop screen, the rest of the screen is dark. The only way to recover is by re-starting the window manager (Ctrl+Alt+Backspace) or by switching to one of the virtual consoles and switch back.
dell@dell:~$ sudo dpkg -l | grep xserver-xorg-video-nv
i xserver-xorg-video-nv 2.0.0-0ubuntu3 X.Org X server -- NV display driver
dell@dell:~$ lspci -v | grep VGA
01:00.0 VGA compatible controller: nVidia Corporation Quadro NVS 110M / GeForce Go 7300 (rev a1) (prog-if 00 [VGA])