You need to make sure the visual options is set to CUSTOM, then select the options you want. If left in Let Computer Select, some options will be turned off if Windows thinks you don't have enough computational power to run all the options.
I have stumbled across yet another problem with my computer and windows 7. Sometimes show contents while dragging works but other times it just displays a black outline. I have seen it working before and it works if i go to performance options and display and click apply then it works but when i restart it goes back to the black outline. I can live with it but i would like to sort it out.
Thanks for any help.