diff --git a/content/shared/public/nsXULAtomList.h b/content/shared/public/nsXULAtomList.h
index 75282805b3a..9bb2e7005d7 100644
--- a/content/shared/public/nsXULAtomList.h
+++ b/content/shared/public/nsXULAtomList.h
@@ -36,7 +36,6 @@
 
 
 XUL_ATOM(button, "button")
-XUL_ATOM(checkbox, "checkbox")
 XUL_ATOM(spinner, "spinner")
 XUL_ATOM(scrollbar, "scrollbar")
 XUL_ATOM(slider, "slider")
diff --git a/layout/base/nsCSSFrameConstructor.cpp b/layout/base/nsCSSFrameConstructor.cpp
index d29d0b77b1b..5f03a52d785 100644
--- a/layout/base/nsCSSFrameConstructor.cpp
+++ b/layout/base/nsCSSFrameConstructor.cpp
@@ -113,9 +113,6 @@ NS_NewSliderFrame ( nsIFrame** aNewFrame );
 nsresult
 NS_NewScrollbarFrame ( nsIFrame** aNewFrame );
 
-nsresult
-NS_NewTriStateCheckboxFrame ( nsIFrame** aNewFrame );
-
 nsresult
 NS_NewSpinnerFrame ( nsIFrame** aNewFrame );
 
@@ -1859,7 +1856,6 @@ nsCSSFrameConstructor::TableIsValidCellContent(nsIPresContext* aPresContext,
 	    (nsXULAtoms::titledbutton      == tag.get())  ||
         (nsXULAtoms::grippy          == tag.get())  ||
         (nsXULAtoms::splitter        == tag.get())  ||
-        (nsXULAtoms::checkbox        == tag.get())  ||
         (nsXULAtoms::slider == tag.get())  ||
         (nsXULAtoms::spinner == tag.get())  ||
         (nsXULAtoms::scrollbar == tag.get())  ||
@@ -3437,8 +3433,6 @@ nsCSSFrameConstructor::ConstructXULFrame(nsIPresContext*          aPresContext,
     // Create a frame based on the tag
     if (aTag == nsXULAtoms::button)
       rv = ConstructButtonControlFrame(aPresContext, newFrame);
-    else if (aTag == nsXULAtoms::checkbox)
-      rv = NS_NewTriStateCheckboxFrame(&newFrame);
     else if (aTag == nsXULAtoms::spinner)
       rv = NS_NewSpinnerFrame(&newFrame);
     else if (aTag == nsXULAtoms::colorpicker)
diff --git a/layout/html/style/src/nsCSSFrameConstructor.cpp b/layout/html/style/src/nsCSSFrameConstructor.cpp
index d29d0b77b1b..5f03a52d785 100644
--- a/layout/html/style/src/nsCSSFrameConstructor.cpp
+++ b/layout/html/style/src/nsCSSFrameConstructor.cpp
@@ -113,9 +113,6 @@ NS_NewSliderFrame ( nsIFrame** aNewFrame );
 nsresult
 NS_NewScrollbarFrame ( nsIFrame** aNewFrame );
 
-nsresult
-NS_NewTriStateCheckboxFrame ( nsIFrame** aNewFrame );
-
 nsresult
 NS_NewSpinnerFrame ( nsIFrame** aNewFrame );
 
@@ -1859,7 +1856,6 @@ nsCSSFrameConstructor::TableIsValidCellContent(nsIPresContext* aPresContext,
 	    (nsXULAtoms::titledbutton      == tag.get())  ||
         (nsXULAtoms::grippy          == tag.get())  ||
         (nsXULAtoms::splitter        == tag.get())  ||
-        (nsXULAtoms::checkbox        == tag.get())  ||
         (nsXULAtoms::slider == tag.get())  ||
         (nsXULAtoms::spinner == tag.get())  ||
         (nsXULAtoms::scrollbar == tag.get())  ||
@@ -3437,8 +3433,6 @@ nsCSSFrameConstructor::ConstructXULFrame(nsIPresContext*          aPresContext,
     // Create a frame based on the tag
     if (aTag == nsXULAtoms::button)
       rv = ConstructButtonControlFrame(aPresContext, newFrame);
-    else if (aTag == nsXULAtoms::checkbox)
-      rv = NS_NewTriStateCheckboxFrame(&newFrame);
     else if (aTag == nsXULAtoms::spinner)
       rv = NS_NewSpinnerFrame(&newFrame);
     else if (aTag == nsXULAtoms::colorpicker)
diff --git a/layout/macbuild/layout.mcp b/layout/macbuild/layout.mcp
index 400e035484f..325d707d933 100644
Binary files a/layout/macbuild/layout.mcp and b/layout/macbuild/layout.mcp differ
diff --git a/layout/xul/base/src/Makefile.in b/layout/xul/base/src/Makefile.in
index 1859ace6165..8e5d9d278e8 100644
--- a/layout/xul/base/src/Makefile.in
+++ b/layout/xul/base/src/Makefile.in
@@ -54,7 +54,6 @@ CPPSRCS =				\
 	nsTreeIndentationFrame.cpp \
 	nsTreeCellFrame.cpp \
 	nsTreeTwistyListener.cpp \
-	nsTriStateCheckboxFrame.cpp \
 	nsSpinnerFrame.cpp \
 	nsScrollbarFrame.cpp \
 	nsScrollbarButtonFrame.cpp \
diff --git a/layout/xul/base/src/makefile.win b/layout/xul/base/src/makefile.win
index f25c86e9671..71f6b6433f7 100644
--- a/layout/xul/base/src/makefile.win
+++ b/layout/xul/base/src/makefile.win
@@ -42,7 +42,6 @@ CPPSRCS=					\
 	nsTreeIndentationFrame.cpp \
 	nsTreeCellFrame.cpp \
 	nsTreeTwistyListener.cpp \
-	nsTriStateCheckboxFrame.cpp \
 	nsSpinnerFrame.cpp \
 	nsScrollbarFrame.cpp \
         nsScrollbarButtonFrame.cpp \
@@ -75,7 +74,6 @@ CPP_OBJS=					\
 	.\$(OBJDIR)\nsTreeIndentationFrame.obj \
 	.\$(OBJDIR)\nsTreeCellFrame.obj \
 	.\$(OBJDIR)\nsTreeTwistyListener.obj \
-	.\$(OBJDIR)\nsTriStateCheckboxFrame.obj \
 	.\$(OBJDIR)\nsSpinnerFrame.obj \
 	.\$(OBJDIR)\nsScrollbarFrame.obj \
 	.\$(OBJDIR)\nsScrollbarButtonFrame.obj \
diff --git a/layout/xul/content/src/nsXULAtomList.h b/layout/xul/content/src/nsXULAtomList.h
index 75282805b3a..9bb2e7005d7 100644
--- a/layout/xul/content/src/nsXULAtomList.h
+++ b/layout/xul/content/src/nsXULAtomList.h
@@ -36,7 +36,6 @@
 
 
 XUL_ATOM(button, "button")
-XUL_ATOM(checkbox, "checkbox")
 XUL_ATOM(spinner, "spinner")
 XUL_ATOM(scrollbar, "scrollbar")
 XUL_ATOM(slider, "slider")