C3 stacked bar chart order function is not working in safari and IE.

Order function , when returns true,order of data in bar does not change in safari.
here is a demo: https://jsfiddle.net/shru8051/wp520y8j/

var chart = c3.generate({
data: {
columns: [
['MONETARY', 11340, 3259],
['NON-MONETARY', 12335, 18041]
],
type: 'bar',
groups: [
['MONETARY','NON-MONETARY']
],
order:function(t1,t2){return true}, // not working in safari
},

axis: {
x: {
type: 'category',
categories: ['DENTIST', 'PROGRAMMER/ANALYST']
}
}
});