A complicated and controversial measure to change how Florida’s 4,300 public schools get taxpayer money for construction and maintenance projects is limping through the Florida Senate, advancing even as lawmakers agree it needs a lot more work before it might become law. Senators behind the measure (SB 376) envision the final bill would have two main elements: It would require school districts to share local tax dollars with charter schools, and it would give school boards the freedom to raise local tax rates back to pre-recession levels, so that they could collect more revenue to address the backlog of maintenance needs in traditional public schools.