On peaked lapels, there is a often (always?) a bit of thread holding the actual peak of the lapel to the rest of the collar. I always assumed this was meant to remain in place and help the lapel lie flat. Mostly because on the couple of double-breasted jackets I have, the thread is the correct color to 'disappear', and not be noticeable. Today, a colleague with a a new peaked lapel jacket asked if it should be removed, like the thread used to keep pockets and vents closed on new jackets. Thoughts?