I read the article you referred to in El Observatodo. It doesn't say that the princess threw a tantrum. It reported that certain requirements are being demanded by the princess' officials, probably the protocol officers. As I wrote in the comment section, those demands are the hallmarks of an overbearing protocol office typical of royal houses around the world. Some will demand that finger food served in the presence of royalty must fit certain exact measurements and colours as the office thinks fit. The trouble is, the royalty themselves often do not bother with these things but it is the royal court around them who are taking things way too seriously and having a hysterical case of stiff upper lip.