First I would like to say that this is my first try to set up a linux distribution. With taking Debian 7.8 I was probably over estimating myself.I do have the following video card:lspci -nn | grep VGA01:00.0 VGA compatible controller [0300]: Advanced Micro Devices [AMD] nee ATI Whistler [AMD Radeon HD 6600M Series]After the installation I just experienced a black screen. But with the help from wiki.debian.org/ATIProprietary I was able to get rid of the black screen and use Gnome3.But first I had a black screen too, but this time the issue was that during the initialisation the display switches to external monitor. So I plugged in a HDMI cable and I could see that my Gnome3 was working properly. I would like to achieve that when no external monitor cable is plugged in, the monitor does not switch to external. On the other hand it would be nice if it switches to the external monitor if I plug in an external monitor. I do think that this can be achieved by manipulating the xorg.conf file, but sadly I do not know how.EDITxorg.conf looks like this:Section ServerLayout            Identifier     aticonfig Layout            Screen      0  aticonfig-Screen[0]-0 0 0    EndSection    Section Module    EndSection    Section Monitor            Identifier   aticonfig-Monitor[0]-0            Option      VendorName ATI Proprietary Driver            Option      ModelName Generic Autodetecting Monitor            Option      DPMS true    EndSection    Section Device            Identifier  aticonfig-Device[0]-0            Driver      fglrx            BusID       PCI:1:0:0    EndSection    Section Screen            Identifier aticonfig-Screen[0]-0            Device     aticonfig-Device[0]-0            Monitor    aticonfig-Monitor[0]-0            DefaultDepth     24            SubSection Display                    Viewport   0 0                    Depth     24            EndSubSection    EndSectionUsing display in the system settings I was not able to switch to my laptop monitor. I can change the settings for my external monitor and can only mirror the output on my laptop monitor. If you need information, let me know. 
debian wheezy switches from internal to external monitor after AMD proprietary installation
debian;xorg;monitors;amd graphics