--- a/widget/windows/nsWindow.cpp
+++ b/widget/windows/nsWindow.cpp
@@ -610,16 +610,17 @@ nsWindow::nsWindow(bool aIsChildWindow)
   mFutureMarginsToUse   = false;
   mCustomNonClient      = false;
   mHideChrome           = false;
   mFullscreenMode       = false;
   mMousePresent         = false;
   mDestroyCalled        = false;
   mHasTaskbarIconBeenCreated = false;
   mMouseTransparent     = false;
+  mDelayedFocus         = false;
   mPickerDisplayCount   = 0;
   mWindowType           = eWindowType_child;
   mBorderStyle          = eBorderStyle_default;
   mOldSizeMode          = nsSizeMode_Normal;
   mLastSizeMode         = nsSizeMode_Normal;
   mLastSize.width       = 0;
   mLastSize.height      = 0;
   mOldStyle             = 0;
@@ -1621,16 +1622,20 @@ nsWindow::Show(bool bState)
           ::SetWindowPos(mWnd, HWND_TOP, 0, 0, 0, 0, flags);
         }
       }
 
       if (!wasVisible && (mWindowType == eWindowType_toplevel || mWindowType == eWindowType_dialog)) {
         // when a toplevel window or dialog is shown, initialize the UI state
         ::SendMessageW(mWnd, WM_CHANGEUISTATE, MAKEWPARAM(UIS_INITIALIZE, UISF_HIDEFOCUS | UISF_HIDEACCEL), 0);
       }
+      if (mDelayedFocus) {
+        mDelayedFocus = false;
+        ::SendMessageW(mWnd, WM_SETFOCUS, 0, 0);
+      }
     } else {
       // Clear contents to avoid ghosting of old content if we display
       // this window again.
       if (wasVisible && mTransparencyMode == eTransparencyTransparent) {
         if (mCompositorWidgetDelegate) {
           mCompositorWidgetDelegate->ClearTransparentWindow();
         }
       }
@@ -5997,16 +6002,20 @@ nsWindow::ProcessMessage(UINT msg, WPARA
         std::min((int32_t)mmi->ptMaxTrackSize.y,
         std::max((int32_t)mmi->ptMinTrackSize.y, mSizeConstraints.mMinSize.height));
       mmi->ptMaxTrackSize.x = std::min((int32_t)mmi->ptMaxTrackSize.x, mSizeConstraints.mMaxSize.width);
       mmi->ptMaxTrackSize.y = std::min((int32_t)mmi->ptMaxTrackSize.y, mSizeConstraints.mMaxSize.height);
     }
     break;
 
     case WM_SETFOCUS:
+      if (!mIsVisible) {
+        mDelayedFocus = true;
+        break;
+      }
       // If previous focused window isn't ours, it must have received the
       // redirected message.  So, we should forget it.
       if (!WinUtils::IsOurProcessWindow(HWND(wParam))) {
         RedirectedKeyDownMessageManager::Forget();
       }
       if (sJustGotActivate) {
         DispatchFocusToTopLevelWindow(true);
       }

--- a/widget/windows/nsWindow.h
+++ b/widget/windows/nsWindow.h
@@ -541,16 +541,17 @@ protected:
   bool                  mTouchWindow;
   bool                  mDisplayPanFeedback;
   bool                  mHideChrome;
   bool                  mIsRTL;
   bool                  mFullscreenMode;
   bool                  mMousePresent;
   bool                  mDestroyCalled;
   bool                  mOpeningAnimationSuppressed;
+  bool                  mDelayedFocus;
   uint32_t              mBlurSuppressLevel;
   DWORD_PTR             mOldStyle;
   DWORD_PTR             mOldExStyle;
   nsNativeDragTarget*   mNativeDragTarget;
   HKL                   mLastKeyboardLayout;
   nsSizeMode            mOldSizeMode;
   nsSizeMode            mLastSizeMode;
   WindowHook            mWindowHook;