Lightroom cc (2015) an Yosemite on Macbook Pro 2011. In grid view, when I zoom the thumbnails in or out with the pad of the Macbook, the resized grid does'n recognize the window borders and flows on a grey background leaving large grey background zones on the left or on the right. Only when I click somewhere on the thumbnails it adjust the view inside the window. This is a bug and I hope it will be solved as soon as possible!!