--- a/layout/style/nsCSSStyleSheet.cpp
+++ b/layout/style/nsCSSStyleSheet.cpp
@@ -828,16 +828,25 @@ CloneRuleInto(nsICSSRule* aRule, void* a
 struct ChildSheetListBuilder {
   nsRefPtr<nsCSSStyleSheet>* sheetSlot;
   nsCSSStyleSheet* parent;
 
   void SetParentLinks(nsCSSStyleSheet* aSheet) {
     aSheet->mParent = parent;
     aSheet->SetOwningDocument(parent->mDocument);
   }
+
+  static void ReparentChildList(nsCSSStyleSheet* aPrimarySheet,
+                                nsCSSStyleSheet* aFirstChild)
+  {
+    for (nsCSSStyleSheet *child = aFirstChild; child; child = child->mNext) {
+      child->mParent = aPrimarySheet;
+      child->SetOwningDocument(aPrimarySheet->mDocument);
+    }
+  }
 };
   
 PRBool
 nsCSSStyleSheet::RebuildChildList(nsICSSRule* aRule, void* aBuilder)
 {
   PRInt32 type = aRule->GetType();
   if (type < nsICSSRule::IMPORT_RULE) {
     // Keep going till we get to the import rules.
@@ -923,16 +932,18 @@ nsCSSStyleSheetInner::RemoveSheet(nsCSSS
     delete this;
     return;
   }
   if (aSheet == mSheets.ElementAt(0)) {
     mSheets.RemoveElementAt(0);
     NS_ASSERTION(mSheets.Length(), "no parents");
     mOrderedRules.EnumerateForwards(SetStyleSheetReference,
                                     mSheets.ElementAt(0));
+
+    ChildSheetListBuilder::ReparentChildList(mSheets[0], mFirstChild);
   }
   else {
     mSheets.RemoveElement(aSheet);
   }
 }
 
 static void
 AddNamespaceRuleToMap(nsICSSRule* aRule, nsXMLNameSpaceMap* aMap)