diff --git a/harbour/ChangeLog b/harbour/ChangeLog
index 7f08f53278..6d56406908 100644
--- a/harbour/ChangeLog
+++ b/harbour/ChangeLog
@@ -8,6 +8,16 @@
    2002-12-01 13:30 UTC+0100 Foo Bar <foo.bar@foobar.org>
 */
 
+         hb_stack.pPos <= hb_stack.pBase
+      The old condition was generating usable error message only in the
+      startup function. In deeply called functions it was only waste of
+      CPU time on one of the most often call functions. Before it was
+      activated internal stack structures were corrupted.
+      If we were leaving for many years without really working stack
+      underflow protection then maybe we should think about disabling
+      it at when HB_STACK_MACROS are used and keep it only in real
+      stack functions for HVM developers. Single protection in
+      hb_stackOldFrame() I've just added is enough for basic C code
       validation.
       I created the second version of stack macros without it in
       hbstack.h but I would like to hear other developers opinion.
diff --git a/harbour/include/hbclass.ch b/harbour/include/hbclass.ch
index 186d5bd053..d6b491947d 100644
--- a/harbour/include/hbclass.ch
+++ b/harbour/include/hbclass.ch
@@ -473,9 +473,11 @@ DECLARE HBClass ;
       _HB_MEMBER {[AS <type>] <DataNames>} ;;
       s_oClass:AddMultiData( <(type)>, <uValue>, __HB_CLS_SCOPE( <.export.>, <.protect.>, <.hidde.> ) + iif( <.ro.>, HB_OO_CLSTP_READONLY, 0 ) + iif( <.persistent.>, HB_OO_CLSTP_PERSIST, 0 ), {<(DataNames)>}, __HB_CLS_NOINI )
 
+   /* Warning! For backward compatibility this CLASSDATA ignores the
+      SHARED clause and always create shared class variables */
    #xcommand CLASSDATA <DataNames,...> [ AS <type> ] [ INIT <uValue> ] [<export: EXPORTED, VISIBLE>] [<protect: PROTECTED>] [<hidde: HIDDEN>] [<ro: READONLY, RO>] [<share: SHARED>] [<persistent: PERSISTENT, PROPERTY>] => ;
       _HB_MEMBER {[AS <type>] <DataNames>} ;;
-   s_oClass:AddMultiClsData( <(type)>, <uValue>, __HB_CLS_SCOPE( <.export.>, <.protect.>, <.hidde.> ) + iif( <.ro.>, HB_OO_CLSTP_READONLY, 0 ) + iif( <.share.>, HB_OO_CLSTP_SHARED, 0 ) + iif( <.persistent.>, HB_OO_CLSTP_PERSIST, 0 ), {<(DataNames)>}, __HB_CLS_NOINI )
+   s_oClass:AddMultiClsData( <(type)>, <uValue>, __HB_CLS_SCOPE( <.export.>, <.protect.>, <.hidde.> ) + iif( <.ro.>, HB_OO_CLSTP_READONLY, 0 ) + iif( /* <.share.> */ .T., HB_OO_CLSTP_SHARED, 0 ) + iif( <.persistent.>, HB_OO_CLSTP_PERSIST, 0 ), {<(DataNames)>}, __HB_CLS_NOINI )
 
 #endif /* HB_CLS_FWO */
 
@@ -512,9 +514,4 @@ DECLARE HBClass ;
    _HB_MEMBER {[AS <type>] <DataNames>} ;;
    s_oClass:AddMultiClsData( <(type)>, <uValue>, __HB_CLS_SCOPE( <.export.>, <.protect.>, <.hidde.> ) + iif( <.ro.>, HB_OO_CLSTP_READONLY, 0 ) + iif( <.share.>, HB_OO_CLSTP_SHARED, 0 ) + iif( <.persistent.>, HB_OO_CLSTP_PERSIST, 0 ), {<(DataNames)>}, __HB_CLS_NOINI )
 
-/*
- * Why CLASSDATA was always shared?
- *    - I changed it to respect SHARED definition clause. [druzus]
- */
-
 #endif /* HB_CLASS_CH_ */
diff --git a/harbour/include/hbexprc.c b/harbour/include/hbexprc.c
index d2639be14b..9bed0836b1 100644
--- a/harbour/include/hbexprc.c
+++ b/harbour/include/hbexprc.c
@@ -90,6 +90,19 @@ static void hb_compExprSendPopPush( HB_EXPR_PTR pObj )
       }
       /* Push object */
       HB_EXPR_USE( pObj->value.asMessage.pObject, HB_EA_PUSH_PCODE );
+#ifndef HB_USE_OBJMSG_REF
+      /* Now push current value of variable */
+      if( pObj->value.asMessage.szMessage )
+      {
+         HB_EXPR_PCODE2( hb_compGenMessage, pObj->value.asMessage.szMessage, TRUE );
+      }
+      else
+      {
+         HB_EXPR_USE( pObj->value.asMessage.pMessage, HB_EA_PUSH_PCODE );
+      }
+      /* Push object */
+      HB_EXPR_USE( pObj->value.asMessage.pObject, HB_EA_PUSH_PCODE );
+#endif
    }
    else
    {
@@ -104,6 +117,19 @@ static void hb_compExprSendPopPush( HB_EXPR_PTR pObj )
          /* Push WITHOBJECTMESSAGE pcode */
          HB_EXPR_PCODE2( hb_compGenMessage, NULL, FALSE );
       }
+#ifndef HB_USE_OBJMSG_REF
+      /* Now push current value of variable */
+      if( pObj->value.asMessage.szMessage )
+      {
+         HB_EXPR_PCODE2( hb_compGenMessage, pObj->value.asMessage.szMessage, FALSE );
+      }
+      else
+      {
+         HB_EXPR_USE( pObj->value.asMessage.pMessage, HB_EA_PUSH_PCODE );
+         /* Push WITHOBJECTMESSAGE pcode */
+         HB_EXPR_PCODE2( hb_compGenMessage, NULL, FALSE );
+      }
+#endif
    }
 }
 
@@ -134,9 +160,6 @@ void hb_compExprPushOperEq( HB_EXPR_PTR pSelf, BYTE bOpEq )
     */
    if( pSelf->value.asOperator.pLeft->ExprType == HB_ET_SEND )
    {
-      HB_EXPR_PCODE1( hb_compExprSendPopPush, pSelf->value.asOperator.pLeft );
-      /* Do it. */
-      HB_EXPR_GENPCODE1( hb_compGenPCode1, HB_P_PUSHOVARREF );
 
 /* NOTE: COMPATIBILITY ISSUE:
  *  The above HB_C52_STRICT setting determines
@@ -163,26 +186,48 @@ void hb_compExprPushOperEq( HB_EXPR_PTR pSelf, BYTE bOpEq )
  *   be changed
  */
 
-      /* push increment value */
-      HB_EXPR_USE( pSelf->value.asOperator.pRight, HB_EA_PUSH_PCODE );
-      /* increase operation */
-      switch( bOpEq )
+      HB_EXPR_PCODE1( hb_compExprSendPopPush, pSelf->value.asOperator.pLeft );
+      /* Do it. */
+
+      /* Temporary disabled optimization with references to object variables
+         untill we will not have extended reference items in our HVM [druzus] */
+#ifdef HB_USE_OBJMSG_REF
+      if( bOpEq == HB_P_PLUS || bOpEq == HB_P_MINUS ||
+          bOpEq == HB_P_MULT || bOpEq == HB_P_DIVIDE )
       {
-         case HB_P_PLUS:
-            bOpEq = HB_P_PLUSEQ;
-            break;
-         case HB_P_MINUS:
-            bOpEq = HB_P_MINUSEQ;
-            break;
-         case HB_P_MULT:
-            bOpEq = HB_P_MULTEQ;
-            break;
-         case HB_P_DIVIDE:
-            bOpEq = HB_P_DIVEQ;
-            break;
+         HB_EXPR_GENPCODE1( hb_compGenPCode1, HB_P_PUSHOVARREF );
+
+         /* push increment value */
+         HB_EXPR_USE( pSelf->value.asOperator.pRight, HB_EA_PUSH_PCODE );
+         /* increase operation */
+         switch( bOpEq )
+         {
+            case HB_P_PLUS:
+               bOpEq = HB_P_PLUSEQ;
+               break;
+            case HB_P_MINUS:
+               bOpEq = HB_P_MINUSEQ;
+               break;
+            case HB_P_MULT:
+               bOpEq = HB_P_MULTEQ;
+               break;
+            case HB_P_DIVIDE:
+               bOpEq = HB_P_DIVEQ;
+               break;
+         }
+         HB_EXPR_GENPCODE1( hb_compGenPCode1, bOpEq );
+      }
+      else
+#endif
+      {
+         HB_EXPR_GENPCODE2( hb_compGenPCode2, HB_P_SENDSHORT, 0, ( BOOL ) 1 );
+         /* push increment value */
+         HB_EXPR_USE( pSelf->value.asOperator.pRight, HB_EA_PUSH_PCODE );
+         /* increase operation */
+         HB_EXPR_GENPCODE1( hb_compGenPCode1, bOpEq );
+         /* call pop message with one argument */
+         HB_EXPR_GENPCODE2( hb_compGenPCode2, HB_P_SENDSHORT, 1, ( BOOL ) 1 );
       }
-      HB_EXPR_GENPCODE1( hb_compGenPCode1, bOpEq );
-      
       return;
    }
    /* TODO: add a special code for arrays to correctly handle a[ i++ ]++
@@ -308,28 +353,48 @@ void hb_compExprUseOperEq( HB_EXPR_PTR pSelf, BYTE bOpEq )
    {
       HB_EXPR_PCODE1( hb_compExprSendPopPush, pSelf->value.asOperator.pLeft );
       /* Do it.*/
-      HB_EXPR_GENPCODE1( hb_compGenPCode1, HB_P_PUSHOVARREF );
 
-      /* push increment value */
-      HB_EXPR_USE( pSelf->value.asOperator.pRight, HB_EA_PUSH_PCODE );
-      /* increase operation and pop the unneeded value from the stack */
-      switch( bOpEq )
+      /* Temporary disabled optimization with references to object variables
+         untill we will not have extended reference items in our HVM [druzus] */
+#ifdef HB_USE_OBJMSG_REF
+      if( bOpEq == HB_P_PLUS || bOpEq == HB_P_MINUS ||
+          bOpEq == HB_P_MULT || bOpEq == HB_P_DIVIDE )
       {
-         case HB_P_PLUS:
-            bOpEq = HB_P_PLUSEQPOP;
-            break;
-         case HB_P_MINUS:
-            bOpEq = HB_P_MINUSEQPOP;
-            break;
-         case HB_P_MULT:
-            bOpEq = HB_P_MULTEQPOP;
-            break;
-         case HB_P_DIVIDE:
-            bOpEq = HB_P_DIVEQPOP;
-            break;
+         HB_EXPR_GENPCODE1( hb_compGenPCode1, HB_P_PUSHOVARREF );
+
+         /* push increment value */
+         HB_EXPR_USE( pSelf->value.asOperator.pRight, HB_EA_PUSH_PCODE );
+         /* increase operation and pop the unneeded value from the stack */
+         switch( bOpEq )
+         {
+            case HB_P_PLUS:
+               bOpEq = HB_P_PLUSEQPOP;
+               break;
+            case HB_P_MINUS:
+               bOpEq = HB_P_MINUSEQPOP;
+               break;
+            case HB_P_MULT:
+               bOpEq = HB_P_MULTEQPOP;
+               break;
+            case HB_P_DIVIDE:
+               bOpEq = HB_P_DIVEQPOP;
+               break;
+         }
+         HB_EXPR_GENPCODE1( hb_compGenPCode1, bOpEq );
+      }
+      else
+#endif
+      {
+         HB_EXPR_GENPCODE2( hb_compGenPCode2, HB_P_SENDSHORT, 0, ( BOOL ) 1 );
+         /* push increment value */
+         HB_EXPR_USE( pSelf->value.asOperator.pRight, HB_EA_PUSH_PCODE );
+         /* increase operation */
+         HB_EXPR_GENPCODE1( hb_compGenPCode1, bOpEq );
+         /* Now do the assignment - call pop message with one argument */
+         HB_EXPR_GENPCODE2( hb_compGenPCode2, HB_P_SENDSHORT, 1, ( BOOL ) 1 );
+         /* pop the unneeded value from the stack */
+         HB_EXPR_GENPCODE1( hb_compGenPCode1, HB_P_POP );
       }
-      HB_EXPR_GENPCODE1( hb_compGenPCode1, bOpEq );
-      
       return;
    }
    /* TODO: add a special code for arrays to correctly handle a[ i++ ]++
@@ -455,6 +520,10 @@ void hb_compExprPushPreOp( HB_EXPR_PTR pSelf, BYTE bOper )
    {
       HB_EXPR_PCODE1( hb_compExprSendPopPush, pSelf->value.asOperator.pLeft );
       /* Do it. */
+
+      /* Temporary disabled optimization with references to object variables
+         untill we will not have extended reference items in our HVM [druzus] */
+#ifdef HB_USE_OBJMSG_REF
       HB_EXPR_GENPCODE1( hb_compGenPCode1, HB_P_PUSHOVARREF );
 
       /* increase/decrease operation */
@@ -467,6 +536,13 @@ void hb_compExprPushPreOp( HB_EXPR_PTR pSelf, BYTE bOper )
       bOper = ( bOper == HB_P_INC ) ? HB_P_PLUSEQ : HB_P_MINUSEQ;
 
       HB_EXPR_GENPCODE1( hb_compGenPCode1, bOper );
+#else
+      HB_EXPR_GENPCODE2( hb_compGenPCode2, HB_P_SENDSHORT, 0, ( BOOL ) 1 );
+      /* increase/decrease operation */
+      HB_EXPR_GENPCODE1( hb_compGenPCode1, bOper );
+      /* Now, do the assignment - call pop message with one argument - it leaves the value on the stack */
+      HB_EXPR_GENPCODE2( hb_compGenPCode2, HB_P_SENDSHORT, 1, ( BOOL ) 1 );
+#endif
    }
    else
    {