I’m using Omeka S versión 3.1.2 when I create a new Item and I want to choose more than one Item Set to add but as soon as I choose the first one, I obtain the message “All item sets have been added” and there isn’t any button to choose another one.
I notice there’s some changes in the text and translations between your screenshots (Conjuntos de fichas vs Colecciones, etc.): were these taken at two different times? Or with different language settings? Just making sure we’re getting an accurate picture of the “before” and “after” of your issue as it stands now.
I also see in the second screenshot that you’re using the “filter” function by typing in the box above the set of selections. Does it seem like using or not using that filter affects what you’re able to add? For example, does the problem only happen if you first filter the results down to the one set you’re looking for and then add it? Versus just adding from the unfiltered list?
I think we have a handle on the bug: pretty sure that it happens if you add everything that matches your current filter (so if you filter down to the exact set you want, then add it, you end up in this situation). We have a fix in the works.