diff --git a/mozilla/content/base/public/nsIDocument.h b/mozilla/content/base/public/nsIDocument.h
index 8f185e6ba46..22919206f1a 100644
--- a/mozilla/content/base/public/nsIDocument.h
+++ b/mozilla/content/base/public/nsIDocument.h
@@ -298,9 +298,9 @@ public:
    * it affects a frame model irreversibly, and plays even though
    * the document no longer contains bidi data.
    */
-  void SetBidiEnabled(PRBool aBidiEnabled)
+  void SetBidiEnabled()
   {
-    mBidiEnabled = aBidiEnabled;
+    mBidiEnabled = PR_TRUE;
   }
   
   /**
diff --git a/mozilla/content/base/src/nsGenericDOMDataNode.cpp b/mozilla/content/base/src/nsGenericDOMDataNode.cpp
index 328ff81a1a8..d6d3789bc6e 100644
--- a/mozilla/content/base/src/nsGenericDOMDataNode.cpp
+++ b/mozilla/content/base/src/nsGenericDOMDataNode.cpp
@@ -632,7 +632,7 @@ nsGenericDOMDataNode::BindToTree(nsIDocument* aDocument, nsIContent* aParent,
     // XXX See the comment in nsGenericElement::BindToTree
     mParentPtrBits |= PARENT_BIT_INDOCUMENT;
     if (mText.IsBidi()) {
-      aDocument->SetBidiEnabled(PR_TRUE);
+      aDocument->SetBidiEnabled();
     }
   }
 
@@ -1024,7 +1024,7 @@ void nsGenericDOMDataNode::SetBidiStatus()
   mText.SetBidiFlag();
 
   if (document && mText.IsBidi()) {
-    document->SetBidiEnabled(PR_TRUE);
+    document->SetBidiEnabled();
   }
 }
 
diff --git a/mozilla/layout/base/nsCaret.cpp b/mozilla/layout/base/nsCaret.cpp
index 88a58c3f2ec..11bcecafa7d 100644
--- a/mozilla/layout/base/nsCaret.cpp
+++ b/mozilla/layout/base/nsCaret.cpp
@@ -1233,7 +1233,7 @@ nsresult nsCaret::UpdateHookRect(nsPresContext* aPresContext,
   if (isCaretRTL)
   {
     bidiEnabled = PR_TRUE;
-    aPresContext->SetBidiEnabled(bidiEnabled);
+    aPresContext->SetBidiEnabled();
   }
   else
     bidiEnabled = aPresContext->BidiEnabled();
diff --git a/mozilla/layout/base/nsPresContext.cpp b/mozilla/layout/base/nsPresContext.cpp
index acc5b9072b6..31962737ae4 100644
--- a/mozilla/layout/base/nsPresContext.cpp
+++ b/mozilla/layout/base/nsPresContext.cpp
@@ -1253,12 +1253,12 @@ nsPresContext::BidiEnabledExternal() const
 }
 
 void
-nsPresContext::SetBidiEnabled(PRBool aBidiEnabled) const
+nsPresContext::SetBidiEnabled() const
 {
   if (mShell) {
     nsIDocument *doc = mShell->GetDocument();
     if (doc) {
-      doc->SetBidiEnabled(aBidiEnabled);
+      doc->SetBidiEnabled();
     }
   }
 }
@@ -1286,7 +1286,7 @@ nsPresContext::SetBidi(PRUint32 aSource, PRBool aForceRestyle)
   Document()->SetBidiOptions(aSource);
   if (IBMBIDI_TEXTDIRECTION_RTL == GET_BIDI_OPTION_DIRECTION(aSource)
       || IBMBIDI_NUMERAL_HINDI == GET_BIDI_OPTION_NUMERAL(aSource)) {
-    SetBidiEnabled(PR_TRUE);
+    SetBidiEnabled();
   }
   if (IBMBIDI_TEXTTYPE_VISUAL == GET_BIDI_OPTION_TEXTTYPE(aSource)) {
     SetVisualMode(PR_TRUE);
diff --git a/mozilla/layout/base/nsPresContext.h b/mozilla/layout/base/nsPresContext.h
index 94f7ec9d685..7c626df7368 100644
--- a/mozilla/layout/base/nsPresContext.h
+++ b/mozilla/layout/base/nsPresContext.h
@@ -613,7 +613,7 @@ public:
    *
    *  @lina 07/12/2000
    */
-  NS_HIDDEN_(void) SetBidiEnabled(PRBool aBidiEnabled) const;
+  NS_HIDDEN_(void) SetBidiEnabled() const;
 
   /**
    *  Set visual or implicit mode into the pres context.
diff --git a/mozilla/layout/generic/nsPageFrame.cpp b/mozilla/layout/generic/nsPageFrame.cpp
index 74f799b0198..e1742b48dc1 100644
--- a/mozilla/layout/generic/nsPageFrame.cpp
+++ b/mozilla/layout/generic/nsPageFrame.cpp
@@ -371,7 +371,9 @@ nsPageFrame::DrawHeaderFooter(nsIRenderingContext& aRenderingContext,
       return; // bail if couldn't find the correct length
     }
     
-    PresContext()->SetBidiEnabled(HasRTLChars(str));
+    if (HasRTLChars(str)) {
+      PresContext()->SetBidiEnabled();
+    }
 
     // cacl the x and y positions of the text
     nscoord x = GetXPosition(aRenderingContext, aRect, aJust, str);
diff --git a/mozilla/layout/style/nsRuleNode.cpp b/mozilla/layout/style/nsRuleNode.cpp
index 0519b22b978..2c5c2095b29 100644
--- a/mozilla/layout/style/nsRuleNode.cpp
+++ b/mozilla/layout/style/nsRuleNode.cpp
@@ -3329,7 +3329,7 @@ nsRuleNode::ComputeVisibilityData(void* aStartStruct,
   if (eCSSUnit_Enumerated == displayData.mDirection.GetUnit()) {
     visibility->mDirection = displayData.mDirection.GetIntValue();
     if (NS_STYLE_DIRECTION_RTL == visibility->mDirection)
-      mPresContext->SetBidiEnabled(PR_TRUE);
+      mPresContext->SetBidiEnabled();
   }
   else if (eCSSUnit_Inherit == displayData.mDirection.GetUnit()) {
     inherited = PR_TRUE;
diff --git a/mozilla/layout/xul/base/src/nsTextBoxFrame.cpp b/mozilla/layout/xul/base/src/nsTextBoxFrame.cpp
index ae4dc8f172b..830fdbf78dc 100644
--- a/mozilla/layout/xul/base/src/nsTextBoxFrame.cpp
+++ b/mozilla/layout/xul/base/src/nsTextBoxFrame.cpp
@@ -495,7 +495,7 @@ nsTextBoxFrame::PaintTitle(nsIRenderingContext& aRenderingContext,
     nsresult rv = NS_ERROR_FAILURE;
 
     if (mState & NS_FRAME_IS_BIDI) {
-      presContext->SetBidiEnabled(PR_TRUE);
+      presContext->SetBidiEnabled();
       nsBidiPresUtils* bidiUtils = presContext->GetBidiUtils();
 
       if (bidiUtils) {
diff --git a/mozilla/layout/xul/base/src/tree/src/nsTreeBodyFrame.cpp b/mozilla/layout/xul/base/src/tree/src/nsTreeBodyFrame.cpp
index d73d7838698..f7ef5d71f0d 100644
--- a/mozilla/layout/xul/base/src/tree/src/nsTreeBodyFrame.cpp
+++ b/mozilla/layout/xul/base/src/tree/src/nsTreeBodyFrame.cpp
@@ -1315,21 +1315,16 @@ nsTreeBodyFrame::CheckTextForBidi(nsAutoString& aText)
   const PRUnichar* text = aText.get();
   PRUint32 length = aText.Length();
   PRUint32 i;
-  PRBool maybeRTL = PR_FALSE;
   for (i = 0; i < length; ++i) {
     PRUnichar ch = text[i];
     // To simplify things, anything that could be a surrogate or RTL
     // presentation form is covered just by testing >= 0xD800). It's fine to
     // enable bidi in rare cases where it actually isn't needed.
     if (ch >= 0xD800 || IS_IN_BMP_RTL_BLOCK(ch)) {
-      maybeRTL = PR_TRUE;
+      PresContext()->SetBidiEnabled();
       break;
     }
   }
-  if (!maybeRTL)
-    return;
-
-  PresContext()->SetBidiEnabled(PR_TRUE);
 }
 
 void