diff --git a/layout/generic/nsGfxScrollFrame.cpp b/layout/generic/nsGfxScrollFrame.cpp
index 31bd5169118..062e6885d67 100644
--- a/layout/generic/nsGfxScrollFrame.cpp
+++ b/layout/generic/nsGfxScrollFrame.cpp
@@ -1415,7 +1415,7 @@ nsGfxScrollFrameInner::Layout(nsBoxLayoutState& aState)
   if (mHasVerticalScrollbar && mVScrollbarBox) {
     SetAttribute(mVScrollbarBox, nsXULAtoms::maxpos, maxY);
     SetAttribute(mVScrollbarBox, nsXULAtoms::pageincrement, nscoord(scrollAreaRect.height - fontHeight));
-    SetAttribute(mVScrollbarBox, nsXULAtoms::increment, fontHeight, PR_FALSE);
+    SetAttribute(mVScrollbarBox, nsXULAtoms::increment, fontHeight);
   }
 
   if (mVScrollbarBox) {
diff --git a/layout/html/base/src/nsGfxScrollFrame.cpp b/layout/html/base/src/nsGfxScrollFrame.cpp
index 31bd5169118..062e6885d67 100644
--- a/layout/html/base/src/nsGfxScrollFrame.cpp
+++ b/layout/html/base/src/nsGfxScrollFrame.cpp
@@ -1415,7 +1415,7 @@ nsGfxScrollFrameInner::Layout(nsBoxLayoutState& aState)
   if (mHasVerticalScrollbar && mVScrollbarBox) {
     SetAttribute(mVScrollbarBox, nsXULAtoms::maxpos, maxY);
     SetAttribute(mVScrollbarBox, nsXULAtoms::pageincrement, nscoord(scrollAreaRect.height - fontHeight));
-    SetAttribute(mVScrollbarBox, nsXULAtoms::increment, fontHeight, PR_FALSE);
+    SetAttribute(mVScrollbarBox, nsXULAtoms::increment, fontHeight);
   }
 
   if (mVScrollbarBox) {