diff --git a/ext/fox16_c/include/FXRuby.h b/ext/fox16_c/include/FXRuby.h
index 2c67a27f561c0e55ab535c0a36eda5334d541ce2..c992fe0113836a128bac4da372619204a4e477a5 100644
--- a/ext/fox16_c/include/FXRuby.h
+++ b/ext/fox16_c/include/FXRuby.h
@@ -420,8 +420,8 @@ void FXRbCallVoidArrayMethod(FXDC* recv,const char *func,TYPE objs,FXuint num){
     FXRbUnregisterBorrowedRubyObj(&objs[i]);
   }
 
-FXTreeItem* FXRbCallTreeItemMethod(const FXTreeList* recv,const char *func,FXint x,FXint y);
-FXFoldingItem* FXRbCallFoldingItemMethod(const FXFoldingList* recv,const char *func,FXint x,FXint y);
+FXTreeItem* FXRbCallTreeItemMethod_gvlcb(const FXTreeList* recv,const char *func,FXint x,FXint y);
+FXFoldingItem* FXRbCallFoldingItemMethod_gvlcb(const FXFoldingList* recv,const char *func,FXint x,FXint y);
 
 /* Three arguments */
 template<class TYPE1, class TYPE2, class TYPE3>
diff --git a/ext/fox16_c/include/gvl_wrappers.h b/ext/fox16_c/include/gvl_wrappers.h
index ba2489969c28be3f59852ddeedf2f1ee2114c1ce..df478173992b5472f2250b76f83545c60fc100ce 100644
--- a/ext/fox16_c/include/gvl_wrappers.h
+++ b/ext/fox16_c/include/gvl_wrappers.h
@@ -460,6 +460,16 @@ FOR_EACH_BLOCKING_FUNCTION( DEFINE_GVL_STUB_DECL )
   param(TYPE3, , arg3) \
   param(TYPE4, , arg4)
 
+#define FOR_EACH_PARAM_OF_FXRbCallTreeItemMethod_4(param) \
+  param(ID, , func) \
+  param(TYPE1, , arg1) \
+  param(TYPE2, , arg2)
+
+#define FOR_EACH_PARAM_OF_FXRbCallFoldingItemMethod_4(param) \
+  param(ID, , func) \
+  param(TYPE1, , arg1) \
+  param(TYPE2, , arg2)
+
 
 /* function( name, void_or_nonvoid, returntype, firstparamtype, firstparamname, paramcount ) */
 #define FOR_EACH_CALLBACK_FUNCTION(function) \
@@ -512,6 +522,8 @@ FOR_EACH_BLOCKING_FUNCTION( DEFINE_GVL_STUB_DECL )
   function(FXRbTreeList_sortFunc, GVL_TYPE_NONVOID, FXint, ITEMA, itema, 2) \
   function(FXRbCallDCDrawMethod, GVL_TYPE_VOID, void, RECV, recv, 5) \
   function(FXRbCallDCDrawMethod, GVL_TYPE_VOID, void, RECV, recv, 6) \
+  function(FXRbCallTreeItemMethod, GVL_TYPE_NONVOID, FXTreeItem*, RECV, recv, 4) \
+  function(FXRbCallFoldingItemMethod, GVL_TYPE_NONVOID, FXFoldingItem*, RECV, recv, 4) \
 
 
 FOR_EACH_CALLBACK_FUNCTION( DEFINE_GVLCB_STUB_DECL )