I noticed that the “Text” controls i.e. TextInput, TextArea and RichTextEditor are behaving differently capturing Key strokes. This is happening only on Firefox 2.x on Mac OSx 10.4 where repeated keystrokes are not getting captured and holding down the key does not print the character on the screen.
This has also been logged with Adobe as a bug. If you have solved this problem please let me know.
Scratch Pad 
Are you using Firefox 3 by any chance? If I am not mistaken there are some key event issues with Firefox 3 on Mac. Check out this Firefox bug: https://bugzilla.mozilla.org/show_bug.cgi?id=434399
I am using Firefox 2.0.14
Same here, has been an issue for a while now