Автор: http://www.swissdelphicenter.ch

var
  HookID: THandle;

function MouseProc(nCode: Integer; wParam, lParam: Longint): Longint; stdcall;
var
  szClassName: array[0..255] of Char;
const
  ie_name = 'Internet Explorer_Server';
begin
  case nCode < 0 of
    True:
      Result := CallNextHookEx(HookID, nCode, wParam, lParam)
  else
    case wParam of
      WM_RBUTTONDOWN,
        WM_RBUTTONUP:
        begin
          GetClassName(PMOUSEHOOKSTRUCT(lParam)^.HWND, szClassName,
            SizeOf(szClassName));
          if lstrcmp(@szClassName[0], @ie_name[1]) = 0 then
            Result := HC_SKIP
          else
            Result := CallNextHookEx(HookID, nCode, wParam, lParam);
        end
    else
      Result := CallNextHookEx(HookID, nCode, wParam, lParam);
    end;
  end;
end;

procedure TForm1.FormCreate(Sender: TObject);
begin
  HookID := SetWindowsHookEx(WH_MOUSE, MouseProc, 0, GetCurrentThreadId());
end;

procedure TForm1.FormDestroy(Sender: TObject);
begin
  if HookID <> 0 then
    UnHookWindowsHookEx(HookID);
end;

procedure TForm1.Button1Click(Sender: TObject);
begin
  Webbrowser1.Navigate('http://www.google.com');
end;