Hi Thomas,
Thank you for your answer.
Actually you’re right: this issue is not related to Fixed Widget at all! I read on your website that there could be a problem with Google Chrome, and as my sidebar was in a fixed widget, I thought that it came from your plugin… But after my post I saw that other links out of a fixed widget gave the same bug, and finally it seems to be a conflict between another plugin and my theme. So please forgive me, I was wrong writing to you! I’m quite a novice in solving this kind of issues. For your information, I have tried your two suggestions and it did’nt work, but thank you for your time.
Sylvain