When the window is signalled (by Wayland) to be closed, either by pressing "X" in the Gtk Titlebar or issued by the compositor and multiple tabs are open, only the focused tab is closed.
Created attachment 320282 [details]
Comment on attachment 320282 [details]
Clearing flags on attachment: 320282
Committed r221819: <http://trac.webkit.org/changeset/221819>
All reviewed patches have been landed. Closing bug.