I get this warning a lot in e10s builds. Randomly chosen backtrace is below. aDataType is 0. Breakpoint 1, mozilla::widget::PuppetWidget::GetNativeData (this=0x7fffe655e900, aDataType=0) at /home/dvander/mozilla/mozilla-inbound/widget/xpwidgets/PuppetWidget.cpp:670 670 NS_WARNING("nsWindow::GetNativeData not implemented for this type"); (gdb) bt #0 mozilla::widget::PuppetWidget::GetNativeData (this=0x7fffe655e900, aDataType=0) at /home/dvander/mozilla/mozilla-inbound/widget/xpwidgets/PuppetWidget.cpp:670 #1 0x00007ffff1fd803e in nsDeviceContext::FindScreen (this=0x7fffdedf5700, outScreen=0x7ffffffed188) at /home/dvander/mozilla/mozilla-inbound/gfx/src/nsDeviceContext.cpp:620 #2 0x00007ffff1fd7346 in nsDeviceContext::ComputeFullAreaUsingScreen (this=0x7fffdedf5700, outRect=0x7ffffffed240) at /home/dvander/mozilla/mozilla-inbound/gfx/src/nsDeviceContext.cpp:596 #3 0x00007ffff1fd74c2 in nsDeviceContext::GetRect (this=0x7fffdedf5700, aRect=...) at /home/dvander/mozilla/mozilla-inbound/gfx/src/nsDeviceContext.cpp:435 #4 0x00007ffff2e4fb54 in nsScreen::GetRect (this=0x7fffd6a612e0, aRect=...) at /home/dvander/mozilla/mozilla-inbound/dom/base/nsScreen.cpp:137 #5 0x00007ffff2e4f3dc in nsScreen::GetWidth (this=0x7fffd6a612e0, aRv=...) at /home/dvander/mozilla/mozilla-inbound/dom/base/nsScreen.h:59 #6 0x00007ffff440caf1 in mozilla::dom::ScreenBinding::get_width (cx=0x7fffe65b3880, obj=(JSObject * const) 0x7fffd668a440 [object Screen], self=0x7fffd6a612e0, args=$jsval((JSObject *) 0x7fffd6695a00 [object Function "width"])) at /home/dvander/mozilla/mozilla-inbound/Debug64/dom/bindings/ScreenBinding.cpp:77 #7 0x00007ffff440bb83 in mozilla::dom::ScreenBinding::genericGetter (cx=0x7fffe65b3880, argc=0, vp=0x7ffffffed9e8) at /home/dvander/mozilla/mozilla-inbound/Debug64/dom/bindings/ScreenBinding.cpp:513 #8 0x00007ffff5647e7d in js::CallJSNative (cx=0x7fffe65b3880, native=0x7ffff440b960 <mozilla::dom::ScreenBinding::genericGetter(JSContext*, unsigned int, JS::Value*)>, args=...) at /home/dvander/mozilla/mozilla-inbound/js/src/jscntxtinlines.h:321 #9 0x00007ffff5647849 in js::Invoke (cx=0x7fffe65b3880, args=..., construct=js::NO_CONSTRUCT) at /home/dvander/mozilla/mozilla-inbound/js/src/vm/Interpreter.cpp:481 #10 0x00007ffff5648322 in js::Invoke (cx=0x7fffe65b3880, thisv=..., fval=..., argc=0, argv=0x0, rval=0x7fffe3334660) at /home/dvander/mozilla/mozilla-inbound/js/src/vm/Interpreter.cpp:531 #11 0x00007ffff5648f46 in js::InvokeGetterOrSetter (cx=0x7fffe65b3880, obj=(JSObject *) 0x7fffd668a440 [object Screen], fval=..., argc=0, argv=0x0, rval=0x7fffe3334660) at /home/dvander/mozilla/mozilla-inbound/js/src/vm/Interpreter.cpp:602 #12 0x00007ffff58b456f in js::Shape::get (this=0x7fffd66986a0, cx=0x7fffe65b3880, receiver=(JSObject * const) 0x7fffd668a440 [object Screen], obj=(JSObject *) 0x7fffd668a440 [object Screen], pobj=(JSObject *) 0x7fffd669a430 [object ScreenPrototype] delegate, vp=JSVAL_VOID) at /home/dvander/mozilla/mozilla-inbound/js/src/vm/Shape-inl.h:306 #13 0x00007ffff58a8be1 in NativeGetInline (cx=0x7fffe65b3880, obj=(JSObject * const) 0x7fffd668a440 [object Screen], receiver=(JSObject * const) 0x7fffd668a440 [object Screen], pobj=(JSObject * const) 0x7fffd669a430 [object ScreenPrototype] delegate, shape=0x7fffd66986a0, getHow=0, vp=JSVAL_VOID) at /home/dvander/mozilla/mozilla-inbound/js/src/jsobj.cpp:3837 #14 0x00007ffff58a9fd8 in GetPropertyHelperInline (cx=0x7fffe65b3880, obj=(JSObject * const) 0x7fffd668a440 [object Screen], receiver=(JSObject * const) 0x7fffd668a440 [object Screen], id=$jsid("width"), getHow=0, vp=JSVAL_VOID) at /home/dvander/mozilla/mozilla-inbound/js/src/jsobj.cpp:4008 #15 0x00007ffff58a95c8 in js::GetPropertyHelper (cx=0x7fffe65b3880, obj=(JSObject * const) 0x7fffd668a440 [object Screen], id=$jsid("width"), getHow=0, vp=JSVAL_VOID) at /home/dvander/mozilla/mozilla-inbound/js/src/jsobj.cpp:4017 #16 0x00007ffff56580a6 in GetPropertyOperation (cx=0x7fffe65b3880, fp=0x7fffe33344c0, script=0x7fffd66878f8, pc=0x7fffd6ab33cf "5", lval=JSVAL_VOID, vp=JSVAL_VOID) at /home/dvander/mozilla/mozilla-inbound/js/src/vm/Interpreter.cpp:284 #17 0x00007ffff5641008 in Interpret (cx=0x7fffe65b3880, state=...) at /home/dvander/mozilla/mozilla-inbound/js/src/vm/Interpreter.cpp:2135 #18 0x00007ffff563b9fc in js::RunScript (cx=0x7fffe65b3880, state=...) at /home/dvander/mozilla/mozilla-inbound/js/src/vm/Interpreter.cpp:438 #19 0x00007ffff5647955 in js::Invoke (cx=0x7fffe65b3880, args=..., construct=js::NO_CONSTRUCT) at /home/dvander/mozilla/mozilla-inbound/js/src/vm/Interpreter.cpp:500 #20 0x00007ffff5648322 in js::Invoke (cx=0x7fffe65b3880, thisv=..., fval=..., argc=0, argv=0x7fffffff0cb8, rval=0x7fffffff0c60) at /home/dvander/mozilla/mozilla-inbound/js/src/vm/Interpreter.cpp:531 #21 0x00007ffff5a5006b in js::ion::DoCallFallback (cx=0x7fffe65b3880, frame=0x7fffffff0ce8, stub=0x7fffdc56cc20, argc=0, vp=0x7fffffff0ca8, res=JSVAL_VOID) at /home/dvander/mozilla/mozilla-inbound/js/src/ion/BaselineIC.cpp:7004

I am pretty sure that a solution for bug 706765 will also fix this.