Index: src/sqliteInt.h
==================================================================
--- src/sqliteInt.h
+++ src/sqliteInt.h
@@ -1571,11 +1571,11 @@
 ** Bits of the sqlite3.dbOptFlags field that are used by the
 ** sqlite3_test_control(SQLITE_TESTCTRL_OPTIMIZATIONS,...) interface to
 ** selectively disable various optimizations.
 */
 #define SQLITE_QueryFlattener 0x0001   /* Query flattening */
-                          /*  0x0002   available for reuse */
+#define SQLITE_WindowFunc     0x0002   /* Use xInverse for window functions */
 #define SQLITE_GroupByOrder   0x0004   /* GROUPBY cover of ORDERBY */
 #define SQLITE_FactorOutConst 0x0008   /* Constant factoring */
 #define SQLITE_DistinctOpt    0x0010   /* DISTINCT using indexes */
 #define SQLITE_CoverIdxScan   0x0020   /* Covering index scans */
 #define SQLITE_OrderByIdxJoin 0x0040   /* ORDER BY of joins via index */

Index: src/window.c
==================================================================
--- src/window.c
+++ src/window.c
@@ -1090,11 +1090,11 @@
   pWin = (Window*)sqlite3DbMallocZero(pParse->db, sizeof(Window));
   if( pWin==0 ) goto windowAllocErr;
   pWin->eFrmType = eType;
   pWin->eStart = eStart;
   pWin->eEnd = eEnd;
-  if( eExclude==0 && OptimizationDisabled(pParse->db, SQLITE_QueryFlattener) ){
+  if( eExclude==0 && OptimizationDisabled(pParse->db, SQLITE_WindowFunc) ){
     eExclude = TK_NO;
   }
   pWin->eExclude = eExclude;
   pWin->bImplicitFrame = bImplicitFrame;
   pWin->pEnd = sqlite3WindowOffsetExpr(pParse, pEnd);