I would say that your gpu is an artifact that gives you xserver garbage that is captured by your screen capture software. And again, I'm wrong.
I notice that your problem is very similar to this: Moving and missing lines of code; problem with eclipse xml editor where i noticed"The reason you get weird visual artifacts is that if a file contains broken DOS line endings (multiple carriage returns without a newline for each carriage return)"
, Mac, : All, Copy, Paste ?