I have tryed another add-on that works better than this: "S3.Translator". I proceed to compare them:

- This translator: translate the selected word, but u first got to second click and select the option from the list. After that, the word is translated, but the original word disappear.

- S3.Translator: you just got to select the word and it appears 3 buttoms on it that allows you to listen the word, translate it (in a float windows that you can close after the consultant) and copy the word (this third option is absurd, in my opinionI).