At one stage in the mayhem, an egg was thrown at Tsang and a portrait of Legco president Jasper Tsang Yok-sing was defaced by a tomato.
The pan-democrats who walked out were also protesting against the decision of Jasper Tsang to eject League of Social Democrats lawmaker "Long Hair" Leung Kwok-hung for attempting to raise a question on rules and procedures while Wong was pressing Donald Tsang for an answer. Wong was also expelled.
Donald Tsang accused lawmakers of double standards as they chastised him while forgiving Wong for "offensive" remarks against him.
With the president refusing to retract the expulsion order, or rule the chief executive's remarks to be offensive, 13 pan-democrats left the chamber half way through the question-and-answer session with Donald Tsang on his final policy address.
Later, eight more lawmakers, six from the Democratic Party, walked out.
Donald Tsang said the chief executive and all top officials should be entitled to the same rights as lawmakers when attending Legco meetings and that legislators should not hold a "double standard."
The incident was sparked when Wong - speaking fiercely but without using bad language - asked why Donald Tsang recommended Beijing to appoint Stephen Lam Sui-lung as the chief secretary.
The question asked, Jasper Tsang told Wong to sit down. But instead he went on to accuse Donald Tsang of going against "political ethics," a term Tsang used in his address.
Rebuking Wong, the chief executive said: "Irrespective of Confucius, Aristotle, current politicians or the current political system, none will consider foul language as well as rude speech or acts as appropriate political ethics. It's so simple."
Wong: "Is violence in the legislature considered rude? Is the government's