How did the rise of the black middle class affect segregation laws? How did segregation affect the black middle class?

Though handfuls of privileged and professional Black Americans, comprised particularly of medical professionals who exclusively serviced black communities, have existed in major cities (especially in the North) since the early twentieth century, most Black Americans were excluded from educational and professional work opportunities until the late 1960s. After major civil rights legislation was passed by the Johnson Administration in 1964 (the Civil Rights Act) and 1965 (the Voting Rights Act), the black middle class developed. After the introduction of affirmative action programs (in the late 1960s and early 1970s), which were designed to expand educational and work opportunities for white women and Black Americans, the black middle class expanded.
Even after the end of de jure segregation, or Jim Crow laws, in the American South, black people throughout the United States still suffered from various aspects of discrimination, including housing discrimination, work discrimination, and the ghettoization of black children into chronically underperforming schools. However, your question is specifically about how segregation, presumably legal segregation, affected the black middle class, so I will discuss that.
In the South, black people were excluded from institutions of higher education that were not historically black colleges and universities (HBCUs). Black families going on vacations or road trips were excluded from most public accommodations, which required black travelers to carry The Negro Motorist Green Book, which told them where they could find food and lodging, use restrooms, and obtain fuel. Also, black voters in some states were subject to very difficult citizenship tests that were not demanded from white voters. Even in instances in which black people passed the tests, they were sometimes still forbidden to vote.
It is difficult to pinpoint a single catalyst (I would argue that there isn't one) leading people to challenge their circumstances. I would argue that World War II, the prosperity of the postwar years, and the highly publicized murder of Emmett Till helped to spur the educated middle class in resisting segregation. Many black soldiers served in World War II and likely recognized the hypocrisy of the United States fighting for democracy abroad while not adhering to its own values at home. The prosperity of the postwar years made some black people feel less trapped in poverty, which provided them with more time and means to participate in marches and other protest movements.