Final Cut Pro X 10.1: Scroll bars intermittently disappear (Apple KB)

Apple Knowledge Base's picture

The horizontal and vertical scroll bars might intermittently disappear in the Event Browser and Timeline in Final Cut Pro X 10.1.x. This can occur after you pair a mouse or trackpad with your MacBook Pro (Retina, Late 2013) or Mac Pro (Late 2013).

Read more: http://support.apple.com/kb/TS5438