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procedure WMCNRButtonDown(var Msg: TWMNCRButtonDown); message WM_NCRBUTTONDOWN;
procedure FoldUp;
procedure FoldDown;

procedure TfrmFold.WMCNRButtonDown(var Msg: TWMNCRButtonDown);
var
  h: Integer;
begin
  if (Msg.HitTest = HTCAPTION) then
  begin
    if(ClientHeight = 80) then
    begin
      for h := 80 to fOldClientHeight do
      begin
        ClientHeight := h+1;
      end;
      Application.ProcessMessages;
      pnGround.Height := h;
      FoldDown;
    end
    else
  begin
    fOldClientHeight := ClientHeight;
    for h := fOldClientHeight downto 80 do
    begin
    ClientHeight := h;
    pnGround.Height := h;
    FoldUp;
    end;
    Application.ProcessMessages;
  end;
end;
end;