[Zope] Zope 2.13.26 and Product ExternalEditor

Hello everybody, I would like very badly to upgrade to 2.13.26. The installation of zope is working just fine. The problem appear when I install the product ExternalEditor (ver. 2.0.2). After installing it and restarting zope, all the icons of the products in ZMI disappear… I can see just the pencil icon of the External Editor. Do you have a clue about it? I don’t no why. Any way to fix it? Thanks so much, Giampiero