#668
#668

- Added check to cp.apple.finalcutpro.ui.Window.id to make sure window
is not `nil`
- Closes #668

CommandPost/CommandPost,cailyoung/CommandPost,CommandPost/CommandPost,fcpxhacks/fcpxhacks,fcpxhacks/fcpxhacks,cailyoung/CommandPost,CommandPost/CommandPost,cailyoung/CommandPost