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function GetFocusedControlSelText: String;
var
  focusedHandle, activeWinHandle: HWND;
  focusedThreadID : DWORD;
  pc:PWideChar;
  str:String;
  i,lpos,fpos:integer;
begin
  i:=0;
  Windows.SetFocus(0);
  SetLengtH(str,65536);
  pc := PWideChar(stR);
  activeWinHandle := GetForegroundWindow;
  focusedThreadID := GetWindowThreadProcessID(activeWinHandle, nil) ;
  if AttachThreadInput(GetCurrentThreadID, focusedThreadID, true) then
  try
    focusedHandle := Windows.GetFocus;
    if focusedHandle <> 0 then
    begin
      i := SendMessage(focusedHandle, EM_GETSEL, 0, 0);
      if( i > 0 ) then
      begin
        lpos := (i shr 16) AND $FFFF;
        fpos := i and $FFFF;
        i := SendMessage(focusedHandle, WM_GETTEXT, 65536, Integer(pc));
        if( i <> 0 ) then
        begin
          result := copy(str,fpos+1,lpos-fpos);
        end;
      end;
      SetLength(str,i);
      result := str;
    end
  finally
    AttachThreadInput(GetCurrentThreadID, focusedThreadID, false) ;
  end;
end;
// s. auch: http://embarcadero.newsgroups.archived.at/public.delphi.nativeapi/201006/1006253692.html