I think this may be related to a bug in Scratch Live. Were you dragging and dropping any files just before/as this occured? If it happens again, can you try clicking your mouse inside of Scratch Live, or pressing the up and down cursor keys to see if that stops it. I have reproduced a bug in Scratch Live that occurs when you drag any file over the Scratch Live library/crate and then onto any application window over the Scratch Live window. Essentially this looks like it is just a bug to do with application focus. This is the most likely cause of the problems you are experiencing. I have sent a bug report to the Scratch Live developers at Serato.
