Switching timelines is sometimes throwing an exception, preventing the timeline view from changing back to the overview view. This is a latent bug exposed by switching to ES6 classes / strict mode.
<rdar://problem/20653689>
Created attachment 251339 [details] Patch
Comment on attachment 251339 [details] Patch Clearing flags on attachment: 251339 Committed r183119: <http://trac.webkit.org/changeset/183119>
All reviewed patches have been landed. Closing bug.