Well, I bring a fix: in fact, VDH still works, but now, in the Tools menu choose DownloadHelper does not work (in fact as it is useless as I said ...) By cons, in the bar modules (to be commissioned in View-> Toolbar) I have this little icon and it runs whenever a video is started, and thus allows its registration by the right click, left click giving access to all the options that were previously in the Tools menu ...
Here, I post this in case anyone encounter the problem (I already repaired one English on this subject, so I'm not alone!)
Have a good day !