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My first thought this morning, even before coffee was: "Damn! I forgot to erase all plugin references!"... sorry for that.
Many thanks for all your hints! I'm trying your version, but still it seems to me that it zooms always with the same center... or, at least, it doesn't have the camera always as its center. What am I missing?
I am sorry, but I am always been a "back end" developer, so I still have to grasp all this "fron end" issues...
Many thanks in advance.