x-grid lines in front of y-grid lines?

Is there a way to make the x grid focus lines (the vertical line that shows when you hover over a data point) render in front of the y grid lines (the horizontal lines that are always present)? This is an issue for me because my lines are different colors and the x grid lines are dotted. It looks strange when the dots are in front of the vertical lines.

I know I can do this to control the position of the grid lines relative to the data lines:

```
var chart = c3.generate({
bindto: '#chart',
data: {
...
},
grid: {
lines: {
front: false
}
}
});
```

is there a way to control the grid lines positions relative to each other with out modifying the c3 source?