Showing more tick labels when zoomed

Please check this chart: http://snag.gy/h8PRk.jpg
As you may see, the labels in the subchart fit perfectly, but in the main chart we have most ticks without labels. It seems like c3 currently has the same fit setting for the subchart and for the main chart. This would be great if the main chart would add or remove the labels according to the current zoom. Is that currently possible? If not, can we have it in future?
Thanks anyway, this library is a great thing.