Bugzilla

  nsCOMPtr<nsIContent> containerElement;

  nsCOMPtr<nsIDocShellTreeItem> docShellItem = do_QueryReferent(mContainer);

  nsCOMPtr<nsPIDOMWindow> pwin(do_GetInterface(docShellItem));

  if (pwin) {

    containerElement = do_QueryInterface(pwin->GetFrameElementInternal());

  }

  } else {

    if (mContainer && pwin) {

  if (!containerView)

    return nsnull;

  if (containerElement &&

      containerElement->HasAttr(kNameSpaceID_None, nsGkAtoms::transparent))

    return containerView;

  nsIWidget* outerWidget = containerView->GetNearestWidget(nsnull);

  if (outerWidget &&

      outerWidget->GetTransparencyMode() == eTransparencyTransparent)

    return containerView;

  // see if the containerView has already been hooked into a foreign view manager hierarchy

  // if it has, then we have to hook into the hierarchy too otherwise bad things will happen.

  nsIViewManager* containerVM = containerView->GetViewManager();

  nsIView* pView = containerView;

  do {

    pView = pView->GetParent();

  } while (pView && pView->GetViewManager() == containerVM);

  if (pView)

    return containerView;

  // OK, so the container is not already hooked up into a foreign view manager hierarchy.

  // That means we can choose not to hook ourselves up.

  //

  // If the parent container is a chrome shell and we are a content shell

  // then we won't hook into its view

  // tree. This will improve performance a little bit (especially given scrolling/painting perf bugs)

  // but is really just for peace of mind. This check can be removed if we want to support fancy

  // chrome effects like transparent controls floating over content, transparent Web browsers, and

  // things like that, and the perf bugs are fixed.

  nsCOMPtr<nsIDocShellTreeItem> container(do_QueryReferent(mContainer));

  if (container) {

    nsCOMPtr<nsIDocShellTreeItem> sameTypeParent;

    container->GetSameTypeParent(getter_AddRefs(sameTypeParent));

    if (sameTypeParent)

      return containerView;

  }

  return nsnull;