There’s no erase background feature for chord symbols, is there? If not, I would definitely like to add this as a feature request. Regardless of whether you position chord changes inside or above a grand staff, in a typical big band score you still are going to have potential barline collisions with 4 of 5 reeds, 3 of 4 trumpets, and 3 of 4 trombones.
I’m assuming the workaround here is just to use Shift-X text, which does have an erase background feature. Or does someone have a better way?