In Windows 8 chrome metro mode if we Alt tabbed away from chrome while a tab was loading, we would …

content/browser/renderer_host/render_widget_host_view_win.cc

 // Copyright (c) 2012 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "content/browser/renderer_host/render_widget_host_view_win.h"
 
 #include <algorithm>
 #include <map>
 #include <peninputpanel_i.c>
 
@@ skipping 921 matching lines @@
 bool RenderWidgetHostViewWin::HasFocus() const {
   return ::GetFocus() == m_hWnd;
 }
 
 bool RenderWidgetHostViewWin::IsSurfaceAvailableForCopy() const {
   return !!render_widget_host_->GetBackingStore(false) ||
       !!accelerated_surface_.get();
 }
 
 void RenderWidgetHostViewWin::Show() {
-  if (!is_fullscreen_) {
-    DCHECK(parent_hwnd_);
-    DCHECK(parent_hwnd_ != ui::GetWindowToParentTo(true));
-    SetParent(parent_hwnd_);
-  }
   ShowWindow(SW_SHOW);
-
   WasRestored();
 }
 
 void RenderWidgetHostViewWin::Hide() {
   if (!is_fullscreen_ && GetParent() == ui::GetWindowToParentTo(true)) {
     LOG(WARNING) << "Hide() called twice in a row: " << this << ":" <<
         parent_hwnd_ << ":" << GetParent();
     return;
   }
 
   if (::GetFocus() == m_hWnd)
     ::SetFocus(NULL);
   ShowWindow(SW_HIDE);
 
-  if (!is_fullscreen_) {
-    // Cache the old parent, then orphan the window so we stop receiving
-    // messages.
-    parent_hwnd_ = GetParent();
-    SetParent(NULL);
-  }

[cpu_(ooo_6.6-7.5), 2012/07/10 02:45:18]

do we need the parent_hwnd_ anymore?

-
   WasHidden();
 }
 
 bool RenderWidgetHostViewWin::IsShowing() {
   return !!IsWindowVisible();
 }
 
 gfx::Rect RenderWidgetHostViewWin::GetViewBounds() const {
   CRect window_rect;
   GetWindowRect(&window_rect);
@@ skipping 2185 matching lines @@
 void RenderWidgetHostViewWin::ResetPointerDownContext() {
   // If the default focus on the page is on an edit field and we did not
   // receive a focus change in the context of a pointer down message, it means
   // that the pointer down message occurred on the edit field and we should
   // display the on screen keyboard
   if (!received_focus_change_after_pointer_down_ && virtual_keyboard_)
     DisplayOnScreenKeyboardIfNeeded();
   received_focus_change_after_pointer_down_ = false;
   pointer_down_context_ = false;
 }