diff --git a/mozilla/layout/generic/nsHTMLFrame.cpp b/mozilla/layout/generic/nsHTMLFrame.cpp
index 17eeb6e5509..e43483dd69b 100644
--- a/mozilla/layout/generic/nsHTMLFrame.cpp
+++ b/mozilla/layout/generic/nsHTMLFrame.cpp
@@ -67,7 +67,7 @@ public:
                          nsGUIEvent*     aEvent,
                          nsEventStatus&  aEventStatus);
   NS_IMETHOD IsPercentageBase(PRBool& aBase) const {
-    aBase = PR_FALSE;
+    aBase = PR_TRUE;
     return NS_OK;
   }
 
diff --git a/mozilla/layout/html/base/src/nsHTMLFrame.cpp b/mozilla/layout/html/base/src/nsHTMLFrame.cpp
index 17eeb6e5509..e43483dd69b 100644
--- a/mozilla/layout/html/base/src/nsHTMLFrame.cpp
+++ b/mozilla/layout/html/base/src/nsHTMLFrame.cpp
@@ -67,7 +67,7 @@ public:
                          nsGUIEvent*     aEvent,
                          nsEventStatus&  aEventStatus);
   NS_IMETHOD IsPercentageBase(PRBool& aBase) const {
-    aBase = PR_FALSE;
+    aBase = PR_TRUE;
     return NS_OK;
   }