Opera Sidebar onBlur event doesn't fire when sidebar closing

Question

Listener onBlur works when i click on header of any tab, but event doesn't fire when I click on icon of another sidebar extension or when I close sidebar

opr.sidebarAction.onBlur.addListener(function(w) {
  console.log('on blur event');
});

Seems like doubtful feature in Opera extensions API...

Answer 1

Listener onBlur must be on background page of the extension.