par excample: Quick Translator
https://addons.mozilla.org/de/firefox/addon/quick-translator/
http://igorgladkov.com/extensions/translator.html
the Stable and the Beta version works well in Firefox but not in IceDragon … no translation available in IceDragon 
Hello,
Please check which Firefox version you are using. The extension is not compatible with Firefox 13 which IceDragon is built on. It is most likely the extension has to be updated by its developers.
Regards.
No, its not right, i used the latest beta version of quick translator and i used firefox 13 and it works well … but no problem, cause since today it works well in icedragon too 
… but thank u for quick response