After which election the change came in the attitude of Muslim League and Jinnah?

Hint: The Muslim League, originally known as the All India Muslim League, was a political organisation that led the call for the creation of a separate Muslim country during the partition of British India (1947).

Complete answer:
In 1906, the Muslim League was established to protect the interests of Indian Muslims. The league was initially supported by the British and was largely supportive of their rule, but in 1913 it declared independence for India as its objective. The league and its leaders, especially Mohammed Ali Jinnah, campaigned for Hindu-Muslim unity in a united and independent India for decades. The league did not propose for the establishment of a separate Muslim state until 1940, when India was about to become an independent state. Since it believed that an independent India would be ruled by Hindus, the league advocated for a separate country for India's Muslims.

After the election of 1937 and the composition of the Congress Ministers in the provinces, the Muslim League and Jinnah changed their minds. The League's founders, including Jinnah, declared that Muslims should not seek any justice from Congress.

Jinnah and the Muslim League led the fight for the division of British India into independent Hindu and Muslim nations, and the league became Pakistan's main political party after the country's independence in 1947. It was renamed the All Pakistan Muslim League in that year. However, the league was less successful as a modern political party in Pakistan than it had been as a mass-based pressure group in British India, and its influence and stability steadily diminished.

Therefore, After the election of 1937, the change came in the attitude of Muslim League and Jinnah.

Note: However, the All Pakistan Muslim league was less successful as a modern political party in Pakistan than it had been as a mass-based pressure group in British India, and its influence and stability steadily diminished. The Muslim League lost support in East Pakistan (now Bangladesh) in the 1954 elections, and the party lost power in West Pakistan (now Pakistan) not long after. The party had broken into different branches by the late 1960s, and by the 1970s, it had almost vanished.