--- a/layout/xul/base/src/tree/src/nsTreeBodyFrame.cpp
+++ b/layout/xul/base/src/tree/src/nsTreeBodyFrame.cpp
@@ -539,17 +539,19 @@ NS_IMETHODIMP nsTreeBodyFrame::SetView(n
       sel->SetTree(mTreeBoxObject);
     }
     else {
       NS_NewTreeSelection(mTreeBoxObject, getter_AddRefs(sel));
       mView->SetSelection(sel);
     }
 
     // View, meet the tree.
+    nsWeakFrame weakFrame(this);
     mView->SetTree(mTreeBoxObject);
+    NS_ENSURE_STATE(weakFrame.IsAlive());
     mView->GetRowCount(&mRowCount);
  
     PRBool isInReflow;
     PresContext()->PresShell()->IsReflowLocked(&isInReflow);
     if (!isInReflow) {
       // The scrollbar will need to be updated.
       FullScrollbarsUpdate(PR_FALSE);
     } else if (!mReflowCallbackPosted) {