If you use multiple monitors in your Mac setup, you just might be be interested to find that when OS X Lion (at least the latest Developer Preview) is running full screen apps, it apparently stops supporting usage of multiple displays.
While Lion does support and work with multiple monitors, it doesn’t work so well when you decide to use the newly-designed full-screen mode demonstrated at WWDC 2011. You can mirror or extend your displays like normal, but once you put an app into full screen mode, your primary display becomes your only display, with your additional monitors simply displaying a nice-looking dark linen background.
There has been some speculation as to why this might be the case. OS X Daily points out that full screen apps might have been designed specifically with MacBook users in mind, and was never intended to be used with desktop Macs. The pixel-saving nature of full screen apps just isn’t that useful when hooked up to a larger display – the feature seems to really be pointing at the smaller displays that come standard on MacBooks.
Another possibility is that this is just a bug, quirk, or issue with the Developer Preview of Lion, and that it might be fixed before a final release, enabling the continued use of multiple monitors when using full screen apps.
Whatever the reason is, if Lion comes to retail continuing to handle external displays in this manner, I’ll consider it a massive oversight on Apple’s part. Users of a MacBook (particularly a MacBook Air, where the full screen apps seem the most useful) might enjoy using a full screen app on their main screen, while using an external monitor to display their stocks, picture slides, calendars, and so forth, and it seems like they should have the option to do so. I don’t care if this is the default behavior in the final version of Lion, but Apple needs to at least make this behavior configurable in settings.app.
While the obvious solution is just not to use full screen apps when connected to multiple displays, it’s not a very good solution, and will probably become a common source of irritation for users that wish the employ their computer in this manner.
Your thoughts? Sound off in the comments!