Support are quoting Apple's engineers as saying it is "expected behaviour" under Lion for the MBP's internal display to reactivate upon opening the lid, even if you want to use only your external display. A new version of the clamshell mode-related knowledgebase article (replacing HT3131) is due shortly confirming this.
This is despite:
- the obvious temperature-related benefits that were achievable (under Snow Leopard) by opening your MBP lid whilst continuing to output solely to, say, a 27" cinema display
- the wifi connectivity benefits of having the lid open
- the waste of energy and inefficient use of graphics processing power in needlessly running two active screens (ie if running your MBP in clamshell mode would otherwise make it too hot and/or noisy or you need it open for wifi)
- the negative longer-term impact on the battery and other components from running the MBP any hotter than it needs to be.
If you would like to have the previous behaviour restored, please lobby Apple to change how Lion handles clamshell mode. Options available to them include changing Lion's expected behaviour or adding a user-selectable option within System Preferences.
Feedback can be submitted here:
Potential solution: Apple wants your forum feedback
Please see a post in the following thread and reply to it as you wish. Apple has now reportedly requested that we provide evidence within the forum thread in support of our desire to have the "open lid with screen off" option reinstated (eg the significance of operating temperature differences, levels of reduction in wifi reception, etc). They may then address our concerns with a Lion update.
I have found an awesome work around solution using the magnet tick that will allow gained keyboard and touchpad use.
NOTE:This solution only works for people with starcraft 2 installed.(I am also guessing that any game which takes up the full screen might work as well but have only tested it with starcraft 2)
Step One: Use the magnet to trick your monitor so that your only running your external in full resolution
Step Two: Boot up Starcraft 2 in full screen mode.
Step Three: Once your in full screen mode, go ahead and take the magnet off.
Step Four: You can now minimize or quit Starcraft 2 and your external monitor will stay as the primary with full resolution as well as added keyboard and trackpad functionality.