the bcc->topjets collection is not explictly cleaned with respect to leptons (unlike the collection of AK5 jets, where this is done by the JetLeptonSubtractor() routine). applying the DeltaR cut ensures that we have no double counting

we need the TopTagOverlapSelection module to ensure that in the toptag-category we have at least 1 AK5 jet with DeltaR>1.3 with respect to the TopTag jet. if that's not the case, the chi2 is going to fail, i.e. no hypothesis (no AK5 jet to be assigned to the leptonic top)