What is the ruling on the Festival of the Righteous (Eid al-Abrar) that is held every year in Shawwal?

The innovation of the Eid of the Righteous on the eighth of Shawwal, after fasting the six days of Shawwal, is among the newly invented matters. Sheikh al-Islam Ibn Taymiyyah explicitly stated that it is an innovation which the Salaf did not recommend or practice. He affirmed that it is not an Eid, neither for the righteous nor for the wicked, and it is not permissible to believe it is an Eid or to introduce the rituals of Eids therein. This Eid is accompanied by the mixing of men and women in mosques, handshaking with ignorant expressions, and the preparation of special foods.