Rated 5 out of 5 stars
i too had a problem with the activation icon not showing in an email with proper attachments (jpg, etc). i'm actually still on TB version 3.1.9 because of other add-ons not being updated to handle higher versions. i had to roll slide show back to version 1.4.4 to get the icon back.
Once i find/test updates for those other add-ons, i'll try letting TB update itself & see what happens with the add-ons.