A local watchdog on anti-Semitism said the octogenarian's death is reminiscent of the slaying last year of a Jewish woman by her neighbor.
In a speech three weeks before elections, Orban used language that some critics have argued contains anti-Semitic undertones.
A protester was arrested for holding up a picture of Jews being murdered in the Holocaust.
The Denk movement and its satellite party are projected to win as many votes as the ruling party in the March 21 municipal elections.
As per the organizers' insistence, no officials from the Freedom Party were at the international summit. But their shadow was strongly felt.
A museum dedicated to non-Jewish Polish victims of the Nazis came in for criticism from many circles and will not be built.
While some Jews aided the Nazis, historians point out, they did so under the threat of death and often the fear of mass reprisals.
The Forum Against Anti-Semitism documented an increase to 402 cases of hateful rhetoric in 2017, but also a 25% drop in physical assaults on Jews.
The leaders of the Jewish federations of Sweden, Denmark, Norway and Finland urged lawmakers in Reykjavik to reject a bill proposing to ban the rite.
Andrzej Duda's move advances the bill that has been harshly criticized by Jewish groups and Israeli politicians.