anchor.diff:    TKMSelectableEdit = class(TKMControl)
     private
       fFont: TKMFont;
  -    fText: UnicodeString;
       fLeftIndex: Integer; //The position of the character shown left-most when text does not fit
   
       fCursorPos: Integer;
  
positive.code: 
  function TKMNumericEdit.IsCharValid(Key: WideChar): Boolean;
  begin
    Result := Key in ['0'..'9'];
  end;
  
  
  
negative.code: 
  
  function TKMNumericEdit.KeyDown(Key: Word; Shift: TShiftState): Boolean;
  begin
    Result := KeyEventHandled(Key, Shift);
    inherited KeyDown(Key, Shift);
  