Found!
I had two "Ja Teline V menu", one with only Home item, I delete it and now JA Thumbnail should work with no duplication of images, but I've some problems with "Pagebreak":
1. if I use "show pages" I get the controls in the left bar but in weird look and not usable (see attachment)
2. if I use "show tab" (or sliders) apparently the pagebreak don't work and JA Thumbnail has some issues...
Please, see this article.
Help again, please