Resegregation in charter schools?

A study out of UCLA, covered in the Washington Post, speaks of the growth of charter schools tracking with increases in segregation:

To the authors of the study, the findings point to a civil rights issue: "As the country continues moving steadily towards greater segregation and inequality of education for students of color in schools with lower achievement and graduation rates," the study concludes, "the rapid growth of charter schools has been expanding a sector even more segregated than the public schools."