The captions menu doesn't quite behave like a regular menu of this genre on the Mac. It should dismiss when clicking anywhere outside of it on the page and it should prevent the page from scrolling when attempting to scroll the menu when the menu can't scroll anymore.
<rdar://problem/13900405>
Created attachment 202272 [details] Patch
Created attachment 202275 [details] Patch
Comment on attachment 202275 [details] Patch Nice patch, thanks!
https://trac.webkit.org/changeset/150371