Already fixed.
If I'm admin of group X and I click on "trash" (papelera), then I can see its contents normally. However, if I click on it when I'm a collaborator of a group, a message appears "You do not have rights to perform that action" (which is ok) and after I am taken to my homepage (which doesn't make sense). It's fine if I don't have permissions, but I should stay in the last page I was already (within the group X), and not go anywhere else.