Desc:

  WinVista SP2 x64, UAC is ON, x32 bit JRE and FX are used:
      - FX applet isn't loaded if 7u4 b13 + FX 2.0.3 fcs are used.
      - No such issue for 7u4 + FX 2.1 b14, no such issue for 7u2 + FX 2.0.3 fcs

  On WinXP Pro behaviour is different:
     - no issue if FX 2.0.3 is installed offline
     - the same issue if FX 2.0.3 is installed by FX applet request,
       FX applet loaded OK after browser restart

 See comments for details.