Bugzilla

The additional focus event is from `ContentChild::RecvBlurToChild`,

> #0  0x00007f577cfb884b in nsFocusManager::FireFocusOrBlurEvent(mozilla::EventMessage, mozilla::PresShell*, nsISupports*, bool, bool, mozilla::dom::EventTarget*) (this=0x7f578db654c0, aEventMessage=mozilla::eBlur, aPresShell=0x7f5771a66000, aTarget=0x7f576db06030, aWindowRaised=false, aIsRefocus=false, aRelatedTarget=0x0) at /home/edgar/Workspace/mercurial/mozilla-central/dom/base/nsFocusManager.cpp:2667
#1  0x00007f577cfb8255 in nsFocusManager::SendFocusOrBlurEvent(mozilla::EventMessage, mozilla::PresShell*, mozilla::dom::Document*, nsISupports*, unsigned int, bool, bool, mozilla::dom::EventTarget*) (this=0x7f578db654c0, aEventMessage=mozilla::eBlur, aPresShell=0x7f5771a66000, aDocument=<optimized out>, aTarget=<optimized out>, aFocusMethod=<optimized out>, aWindowRaised=<optimized out>, aIsRefocus=false, aRelatedTarget=0x0) at /home/edgar/Workspace/mercurial/mozilla-central/dom/base/nsFocusManager.cpp:2658
#2  0x00007f577cfba272 in nsFocusManager::BlurImpl(mozilla::dom::BrowsingContext*, mozilla::dom::BrowsingContext*, bool, bool, nsIContent*) (this=0x7f578db654c0, aBrowsingContextToClear=<optimized out>, aAncestorBrowsingContextToFocus=0x7f577386dc00, aIsLeavingDocument=true, aAdjustWidget=<optimized out>, aContentToFocus=0x0) at /home/edgar/Workspace/mercurial/mozilla-central/dom/base/nsFocusManager.cpp:2226
#3  0x00007f577e7ccdcd in mozilla::dom::ContentChild::RecvBlurToChild(mozilla::dom::MaybeDiscarded<mozilla::dom::BrowsingContext> const&, mozilla::dom::MaybeDiscarded<mozilla::dom::BrowsingContext> const&, mozilla::dom::MaybeDiscarded<mozilla::dom::BrowsingContext> const&, bool, bool) (this=<optimized out>, aFocusedBrowsingContext=..., aBrowsingContextToClear=..., aAncestorBrowsingContextToFocus=..., aIsLeavingDocument=true, aAdjustWidget=true) at /home/edgar/Workspace/mercurial/mozilla-central/dom/ipc/ContentChild.cpp:3925

~~The additional focus event is from `ContentChild::RecvBlurToChild`,~~ 
Edited: The additional focus event is from `BrowserChild::RecvActivate`,

> #0  0x00007f577cfb884b in nsFocusManager::FireFocusOrBlurEvent(mozilla::EventMessage, mozilla::PresShell*, nsISupports*, bool, bool, mozilla::dom::EventTarget*) (this=0x7f578db654c0, aEventMessage=mozilla::eFocus, aPresShell=0x7f5771a66000, aTarget=0x7f577386d820, aWindowRaised=false, aIsRefocus=false, aRelatedTarget=0x0) at /home/edgar/Workspace/mercurial/mozilla-central/dom/base/nsFocusManager.cpp:2667
#1  0x00007f577cfb8255 in nsFocusManager::SendFocusOrBlurEvent(mozilla::EventMessage, mozilla::PresShell*, mozilla::dom::Document*, nsISupports*, unsigned int, bool, bool, mozilla::dom::EventTarget*) (this=0x7f578db654c0, aEventMessage=mozilla::eFocus, aPresShell=0x7f5771a66000, aDocument=<optimized out>, aTarget=<optimized out>, aFocusMethod=<optimized out>, aWindowRaised=<optimized out>, aIsRefocus=false, aRelatedTarget=0x0) at /home/edgar/Workspace/mercurial/mozilla-central/dom/base/nsFocusManager.cpp:2658
#2  0x00007f577cfb5396 in nsFocusManager::Focus(nsPIDOMWindowOuter*, mozilla::dom::Element*, unsigned int, bool, bool, bool, bool, bool, nsIContent*) (this=0x7f578db654c0, aWindow=
    0x7f578db95d60, aElement=0x7f576db06030, aFlags=<optimized out>, aIsNewDocument=<optimized out>, aFocusChanged=false, aWindowRaised=<optimized out>, aAdjustWidget=<optimized out>, aFocusInOtherContentProcess=<optimized out>, aContentLostFocus=0x0) at /home/edgar/Workspace/mercurial/mozilla-central/dom/base/nsFocusManager.cpp:2418
#3  0x00007f577cfb64dd in nsFocusManager::WindowRaised(mozIDOMWindowProxy*) (this=0x7f578db654c0, aWindow=<optimized out>) at /home/edgar/Workspace/mercurial/mozilla-central/dom/base/nsFocusManager.cpp:764
#4  0x00007f577fde0f46 in nsWebBrowser::FocusActivate() (this=<optimized out>) at /home/edgar/Workspace/mercurial/mozilla-central/toolkit/components/browser/nsWebBrowser.cpp:1208
#5  0x00007f577e7e2d9a in mozilla::dom::BrowserChild::RecvActivate() (this=<optimized out>) at /home/edgar/Workspace/mercurial/mozilla-central/dom/ipc/BrowserChild.cpp:1384