Nageswararao,
The MouseMove() invoked method is the one from the window (or dialog or control) that starts the drag operation, as it captures the mouse.
So we should use WindowFromPoint() and oWndFromHwnd() as I explained, because the mouse may be out of the boundaries of the window (or dialog or control) that started the drag operation.
if ::lDrag
if ::lCaptured
< ... existing code ... >
// new code begin
if oWndOver:hWnd != ( hOver := WindowFromPoint( nCol, nRow ) )
// oWndOver is static variable
oWndOver := oWndFromHWnd( hOver )
if oWndOver:bDropOver == nil // .and. oWndOver:bDropFiles == nil
CursorNO() // c-function
else
SetCursor( ::oDragCursor:hCursor )
endif
endif
// new code ends
else
< ... existing code ... ?
endif
------------------
HB_FUNC( CURSORNO )
{
hb_retnl( ( LONG ) SetCursor( LoadCursor( 0, IDC_NO ) ) );
}
------------------METHOD MouseMove( nRow, nCol, nKeyFlags ) CLASS TControl
local nOldRow, nOldCol
local hOver, oWndOver, aPoint // new locals
< ......... keep the existing code .....>
else
if ::lMouseDown .and. ;
( Abs( nRow - ::nLastRow ) > 5 .or. Abs( nCol - ::nLastCol ) > 5 ) ;
.and. ! Empty( ::oDragCursor )
// SetCursor( ::oDragCursor:hCursor ) // original code commented out
if ! lDragging
::DragBegin( nRow, nCol, nKeyFlags )
// new code begin
hWndOver = ::hWnd
SetCursor( ::oDragCursor:hCursor )
// new code end
else
if ValType( ::bMMoved ) == "B"
Eval( ::bMMoved, nRow, nCol, nKeyFlags, .T. )
endif
endif
// new code begin
DEFAULT hWndOver := ::hWnd
aPoint = { nRow, nCol }
aPoint = ClientToScreen( ::hWnd, aPoint )
hOver := WindowFromPoint( aPoint[ 2 ], aPoint[ 1 ] )
if hOver != hWndOver
hWndOver = hOver
oWndOver = oWndFromHWnd( hOver )
if oWndOver == nil .or. oWndOver:bDropOver == nil
CursorNO()
else
SetCursor( ::oDragCursor:hCursor )
endif
endif
// new code end
else
return Super:MouseMove( nRow, nCol, nKeyFlags )
endif
endif
return 0
//------------
// In this or some other module, preferably in Cursors.c
//
#pragma BEGINDUMP
#include "hbapi.h"
#include <windows.h>
HB_FUNC( CURSORNO )
{
hb_retnl( ( LONG ) SetCursor( LoadCursor( 0, IDC_NO ) ) );
}
#pragma ENDDUMPNageswararao,
You are getting better day by day 
Please email me your modified control.prg, thanks!