I don't understand why sometimes it highlights one or more files in the right-hand pane in pink, as you can see in this screenshot

It doesn't seem to give me any indication as to why it's alerting me about these files.
It also made a mistake with episodes 10 (at the top), 3, 4 and 6 and seems to think they're from series 2, whilst all the rest are correctly identified as from series 1 (all the files are in a folder titled "The Killing", I have a separate folder titled "The Killing S2" for that).