Hi All, I hope other people have this issue or have an idea. Since I updated to Mavericks I've seen the rainbow wheel appear on occasion but it doesn't show up for more than literally a split second before its gone again. Just casually browsing around and might click on something and the wheel appears for a split second barely even there and its gone again. Has only occurred since upgrading. Computer is original rMBP 15inch. Anybody else noticed this or have suggestions?