1. It is up to the developer of the plugin to keep it compatible with Firefox. 2. Firefox 5.0 isn't supported any longer, only Firefox 3.6.20 and Firefox 6.0.

What's wrong with Firefox 5.0?

Firefox 5.0 / 5.0.1 is missing a half a dozen security fixes that are in 3.6.20 and 6.0. Firefox 6.0 is considered a security update for Firefox 5.0, which was a security update for Firefox 4.0.

Thank you. Where would I go to find out why / how Firefox 6 broke the GWT Developer Plugin? Thansk!

Try posting here. <br /> http://groups.google.com/group/google-web-toolkit

I checked there before I ever came here. People have asked, and gotten no answer.

Looks like the problem is with Google having not released an update yet. See the following link and links within: https://groups.google.com/group/google-web-toolkit/browse_thread/thread/48d34a9fb54af7e6/ddb748430950f08a Here is a link within that article re: a patch for Firefox 6: https://gwt-code-reviews.appspot.com/1523805/ '''If this reply solves your problem, please click "Solved It" next to this reply when <u>signed-in</u> to the forum.''' ------------------------- Not related to your question, but... You need to update some plug-ins: *Plug-in check: https://www-trunk.stage.mozilla.com/en-US/plugincheck/ *Adobe Shockwave for Director Netscape plug-in: [https://support.mozilla.com/en-US/kb/Using%20the%20Shockwave%20plugin%20with%20Firefox#w_installing-shockwave Installing ('''''or Updating''''') the Shockwave plugin with Firefox] *Shockwave Flash (Adobe Flash or Flash): [https://support.mozilla.com/en-US/kb/Managing%20the%20Flash%20plugin#w_updating-flash Updating Flash in Firefox] *Next Generation Java Plug-in for Mozilla browsers: [https://support.mozilla.com/en-US/kb/Using%20the%20Java%20plugin%20with%20Firefox#w_installing-or-updating-java Installing or Updating Java in Firefox]