sub-columns not sortable by default

It seems that nested Columns are by default not sortable. If I have:

Code:

columns:[
{ text: 'Foo',
    columns:[
     {text:'Bar'}
    ]
}]

Then column 'Bar' is not sortable unless I explicitly add

whereas normally a Column would be sortable by default.

Is this an issue? I couldn't find where it is mentioned in the doco (only that 'Group' columns i.e. 'Foo' are not sortable).

Is there a way to override this behaviour?

Thanks,



sub-columns not sortable by default