For some time now Firefox will no longer display applets. It doesn't show the replacement HTML between the applet tags, either. It's as if the applet tag wasn't there at all. Does this ring a bell with anyone?
This is on OS X 10.4.8, with Firefox 126.96.36.199 and MRJPlugin/JavaEmbeddingPlugin 0.9.6 (the latest that's available). On Safari applets work fine (both using 1.4 and 1.5), but that uses a different plugin.