When Mountain Lion arrives this summer, let’s hope that Apple gets serious again about multiple monitor support on the Mac. When Lion arrived, to say such support was an afterthought is being kind to afterthoughts.

For example with the 27-inch iMac, some pros and power users may wish to connect one or two 27-inch Thunderbolt Cinema Displays for a massive amount of screen real estate. This set-up works as expected in Snow Leopard, but Lion is a different story.

Take the case of the Aperture user who likes to see his/her work in full screen detail on the center screen, while having access to, say, Mail, Safari, the Aperture User Manual and the APTS training for Aperture certification on the other screens. Makes sense, right?

Unfortunately, while this works just fine with Snow Leopard, under Lion, the second and/or third screen contents is overlayed with an impenetrable grey linen pattern. This reduces those displays to little more than expensive fake linen. There’s no way to simultaneously view all three screens with any screen in full screen mode in any app that supports full screen mode — not just Aperture.

If the app has multiple windows, you’re in a bit more luck. You can place a second window on a second display, for example, but, overall, Lion pretends users would never want more than one display. That’s taking the “iOS-ifcation” of Mac OS X too far.

To continue our Aperture example, you should be able to run Apple’s photography app in full screen on a secondary display while using your primary display for other apps. Or I could have EyeTV open on a secondary display in full screen watching the news, while I work on email and surf the Web on my primary display.

So, c’mon, Apple if I’m running Mountain Lion on my Mac, I want to be able to have a couple or three apps open in full screen mode simultaneously on multiple monitors.

After all, an iMac, Mac Pro or MacBook with more than one screen running ain’t no iPad or iPhone.

— Dennis Sellers