The display action does not behave as expected, though I didn't have enough time to figure out all details. See the ROOT file attached with dataframe create via df = ROOT.RDataFrame('aod2nanoaod/Events', 'output.root'). Now, following outputs surprise.
1. The dataframe has around 20 columns, though the plain `Display()` action displays just four. The full list of columns is
2. There are several Jet* columns, however, we don't see all with Display('.Jet.', 5):
3. Let's just look at Display(('nMuon', 'Muon_pt'), 5), we see only one value per event though it's a collection of nMuon: