diff --git a/content/base/src/nsGkAtomList.h b/content/base/src/nsGkAtomList.h
--- a/content/base/src/nsGkAtomList.h
+++ b/content/base/src/nsGkAtomList.h
@@ -401,16 +401,17 @@ GK_ATOM(handlers, "handlers")
 GK_ATOM(handlers, "handlers")
 GK_ATOM(HARD, "HARD")
 GK_ATOM(hasSameNode, "has-same-node")
 GK_ATOM(hbox, "hbox")
 GK_ATOM(head, "head")
 GK_ATOM(headers, "headers")
 GK_ATOM(height, "height")
 GK_ATOM(hidden, "hidden")
+GK_ATOM(hiddenfocus, "hiddenfocus")
 GK_ATOM(hidechrome, "hidechrome")
 GK_ATOM(highest, "highest")
 GK_ATOM(horizontal, "horizontal")
 GK_ATOM(hover, "hover")
 GK_ATOM(hr, "hr")
 GK_ATOM(href, "href")
 GK_ATOM(hreflang, "hreflang")
 GK_ATOM(hspace, "hspace")
diff --git a/docshell/base/nsDocShell.cpp b/docshell/base/nsDocShell.cpp
--- a/docshell/base/nsDocShell.cpp
+++ b/docshell/base/nsDocShell.cpp
@@ -296,17 +296,16 @@ nsDocShell::nsDocShell():
     mAllowAuth(PR_TRUE),
     mAllowKeywordFixup(PR_FALSE),
     mFiredUnloadEvent(PR_FALSE),
     mEODForCurrentDocument(PR_FALSE),
     mURIResultedInDocument(PR_FALSE),
     mIsBeingDestroyed(PR_FALSE),
     mIsExecutingOnLoadHandler(PR_FALSE),
     mIsPrintingOrPP(PR_FALSE),
-    mIsOffScreenBrowser(PR_FALSE),
     mSavingOldViewer(PR_FALSE),
     mAppType(nsIDocShell::APP_TYPE_UNKNOWN),
     mChildOffset(0),
     mBusyFlags(BUSY_FLAGS_NONE),
     mMarginWidth(0),
     mMarginHeight(0),
     mItemType(typeContent),
     mDefaultScrollbarPref(Scrollbar_Auto, Scrollbar_Auto),
@@ -3943,18 +3942,17 @@ nsDocShell::GetVisibility(PRBool * aVisi
 
     // if our root view is hidden, we are not visible
     if (view->GetVisibility() == nsViewVisibility_kHide) {
         *aVisibility = PR_FALSE;
         return NS_OK;
     }
 
     // otherwise, we must walk up the document and view trees checking
-    // for a hidden view, unless we're an off screen browser, which 
-    // would make this test meaningless.
+    // for a hidden view.
 
     nsCOMPtr<nsIDocShellTreeItem> treeItem = this;
     nsCOMPtr<nsIDocShellTreeItem> parentItem;
     treeItem->GetParent(getter_AddRefs(parentItem));
     while (parentItem) {
         nsCOMPtr<nsIDocShell> docShell(do_QueryInterface(treeItem));
         docShell->GetPresShell(getter_AddRefs(presShell));
 
@@ -3969,19 +3967,17 @@ nsDocShell::GetVisibility(PRBool * aVisi
             return NS_OK;
         }
 
         nsIContent *shellContent =
             pPresShell->GetDocument()->FindContentForSubDocument(presShell->GetDocument());
         NS_ASSERTION(shellContent, "subshell not in the map");
 
         nsIFrame* frame = pPresShell->GetPrimaryFrameFor(shellContent);
-        PRBool isDocShellOffScreen = PR_FALSE;
-        docShell->GetIsOffScreenBrowser(&isDocShellOffScreen);
-        if (frame && !frame->AreAncestorViewsVisible() && !isDocShellOffScreen) {
+        if (frame && !frame->AreAncestorViewsVisible()) {
             *aVisibility = PR_FALSE;
             return NS_OK;
         }
 
         treeItem = parentItem;
         treeItem->GetParent(getter_AddRefs(parentItem));
     }
 
@@ -3990,30 +3986,16 @@ nsDocShell::GetVisibility(PRBool * aVisi
     if (!treeOwnerAsWin) {
         *aVisibility = PR_TRUE;
         return NS_OK;
     }
 
     // Check with the tree owner as well to give embedders a chance to
     // expose visibility as well.
     return treeOwnerAsWin->GetVisibility(aVisibility);
-}
-
-NS_IMETHODIMP
-nsDocShell::SetIsOffScreenBrowser(PRBool aIsOffScreen) 
-{
-    mIsOffScreenBrowser = aIsOffScreen;
-    return NS_OK;
-}
-
-NS_IMETHODIMP
-nsDocShell::GetIsOffScreenBrowser(PRBool *aIsOffScreen) 
-{
-    *aIsOffScreen = mIsOffScreenBrowser;
-    return NS_OK;
 }
 
 NS_IMETHODIMP
 nsDocShell::SetVisibility(PRBool aVisibility)
 {
     if (!mContentViewer)
         return NS_OK;
     if (aVisibility) {
diff --git a/docshell/base/nsDocShell.h b/docshell/base/nsDocShell.h
--- a/docshell/base/nsDocShell.h
+++ b/docshell/base/nsDocShell.h
@@ -561,17 +561,16 @@ protected:
     PRPackedBool               mAllowImages;
     PRPackedBool               mFocusDocFirst;
     PRPackedBool               mHasFocus;
     PRPackedBool               mCreatingDocument; // (should be) debugging only
     PRPackedBool               mUseErrorPages;
     PRPackedBool               mObserveErrorPages;
     PRPackedBool               mAllowAuth;
     PRPackedBool               mAllowKeywordFixup;
-    PRPackedBool               mIsOffScreenBrowser;
 
     // This boolean is set to true right before we fire pagehide and generally
     // unset when we embed a new content viewer.  While it's true no navigation
     // is allowed in this docshell.
     PRPackedBool               mFiredUnloadEvent;
 
     // this flag is for bug #21358. a docshell may load many urls
     // which don't result in new documents being created (i.e. a new
diff --git a/docshell/base/nsIDocShell.idl b/docshell/base/nsIDocShell.idl
--- a/docshell/base/nsIDocShell.idl
+++ b/docshell/base/nsIDocShell.idl
@@ -63,17 +63,17 @@ interface nsISimpleEnumerator;
 interface nsISimpleEnumerator;
 interface nsIInputStream;
 interface nsIRequest;
 interface nsISHEntry;
 interface nsILayoutHistoryState;
 interface nsISecureBrowserUI;
 interface nsIDOMStorage;
 
-[scriptable, uuid(dc4daea1-b43d-406f-bd62-c2ee879192ad)]
+[scriptable, uuid(cf974f45-d2f1-4bd5-aecd-568a1c4da454)]
 interface nsIDocShell : nsISupports
 {
   /**
    * Loads a given URI.  This will give priority to loading the requested URI
    * in the object implementing	this interface.  If it can't be loaded here
    * however, the URL dispatcher will go through its normal process of content
    * loading.
    *
@@ -458,17 +458,10 @@ interface nsIDocShell : nsISupports
    */
   readonly attribute boolean channelIsUnsafe;
 
   /**
    * Disconnects this docshell's editor from its window, and stores the
    * editor data in the open document's session history entry.
    */
   [noscript, notxpcom] void DetachEditorFromWindow();
-
-  /**
-   * If true, this browser is not visible in the traditional sense, but
-   * is actively being rendered to the screen (ex. painted on a canvas)
-   * and should be treated accordingly.
-   **/
-  attribute boolean isOffScreenBrowser;    
 };
 
diff --git a/layout/generic/nsFrame.cpp b/layout/generic/nsFrame.cpp
--- a/layout/generic/nsFrame.cpp
+++ b/layout/generic/nsFrame.cpp
@@ -3605,16 +3605,30 @@ NS_IMETHODIMP nsFrame::GetOffsetFromView
   return NS_OK;
 }
 
 /* virtual */ PRBool
 nsIFrame::AreAncestorViewsVisible() const
 {
   for (nsIView* view = GetClosestView(); view; view = view->GetParent()) {
     if (view->GetVisibility() == nsViewVisibility_kHide) {
+      // if a hidden view is associated with a deck child with the hiddenfocus
+      // attribute set to true, then we treat the view as visible.
+      nsIFrame* frame = static_cast<nsIFrame*>(view->GetClientData());
+      if (frame) {
+        nsIFrame* parentframe = frame->GetParent();
+        if (parentframe->GetType() == nsGkAtoms::deckFrame) {
+          nsIContent* content = frame->GetContent();
+          if (content && content->AttrValueIs(kNameSpaceID_None,
+                                              nsGkAtoms::hiddenfocus, nsGkAtoms::_true,
+                                              eCaseMatters))
+            continue;
+        }
+      }
+      
       return PR_FALSE;
     }
   }
   return PR_TRUE;
 }
 
 nsIWidget*
 nsIFrame::GetWindow() const