Hello guys! My new iMac 5k is arrived (with even more RAM than what I had requested) and it's great! I've launched it in recovery mode and recovered the backup of my rMBP to get all my stuff ready and it worked great. Now are some days I use it everyday and I have noticed a big problem: Once in a while, if I drag anything in the OS (or accidentally click and move on some image on Chrome/Safari/Browsers) the drag and drop gets stuck and I can't release the element. It happens with everything in the OS, and while it's stuck, I can't click on the menu bar or on the dock. Usually, clicking ESC everything is fixed, but sometimes I need to stop my iMac to fix it. Do you have any clue on how to fix this annoying problem? Thanks!