One of the touted features of the unibody design MacBook Pro line was the introduction of two different graphics processing units [1]. Initially they shared two Nvidia GeForce chipsets. Beginning with the Core i5 and Core i7 models, this was changed to use an Intel HD Graphics chipset and either an Nvidia chipset or an AMD chipset (depending on the model and year of introduction).
This was put forth as a great power savings feature, but as many users have seen it has had unintended consequences. [2, 3, 4]
I have had no real issues involving this until I fired up Photoshop CS5 last night and found that the canvas window was missing! Now to be fair this doesn’t appear to be a problem on Snow Leopard, but nonetheless it was passing strange. After some diligent searching, I discovered that the solution appears to be turning off the automatic graphics switching and rebooting the laptop. (Hint: it’s in the Energy Saver system preference pane)
After doing this all was once again well with Photoshop. So if you encounter some odd graphics issues with your unibody MacBook Pro and Lion, try it and see if it helps.