Late last month, some Adobe Photoshop users reported that the new 2013-edition MacBook Air was exhibiting severe flickering when using some brush tools in Photoshop. It didn't happen with all units, but an Adobe representative said he believed it was a driver or GPU issue, and said Apple would need to fix the issue. Today, a MacRumors tipster tells us the flickering issue has been fixed in the OS X 10.8.5 beta released to developers today. The bug made Photoshop nearly unusable for a number of MacBook Air users. Some users have previously suggested t