Cascades makes composer hang

1) On Mac OS X cascades crashes Mozilla hard for all versions of 1.3
   this issue should be fixed by the relase of 1.3.1 and is already
   fixed on the trunk

however ...
2) http://bugzilla.mozilla.org/show_bug.cgi?id=199076

           Summary: cascades makes composer hang
           Product: Browser
           Version: Trunk
          Platform: Macintosh
               URL: http://daniel.glazman.free.fr/composer/cascades02.htm
        OS/Version: MacOS X
            Status: NEW
          Severity: major
          Priority: --
         Component: Installer: XPI Packages
        AssignedTo: ssu <at> netscape.com
        ReportedBy: mozilla <at> mathiesen.info
         QAContact: gbush <at> netscape.com

Mozilla/5.0 (Macintosh; U; PPC Mac OS X Mach-O; rv:1.4a;) Gecko/20030324

1) install cascades on a fresh build
2) open composer
3) activate cascades

results:
1) it's impossible to create a new stylesheet
2) it's impossible to close cascades