[Wlug] context menu in mozilla 0.9.9

hi, I want to put a URL link to one of the context menus in Mozilla. Do you think it is possible? Do you think I have to deal with the source of the program?(which I don't think I can) Or is there another way to alter the values in the context menus? For example, I will highlight a word on a web page, and when right click on it, mozilla will query dict.org with my highlighted word, on a new browser window. I hope my question is clear. thanks, baris