Sort rows when eXcell type custom

Hi,

I want sort my grid by a dhxCalendar type, but Read-only.

When the type is simple dhxCalendar the sorting is OK.
But when I make a custom type I can’t sort this column (nothing happens).

I think there is a problem with my custom function, but I don’t know what…

function eXcell_datero(cell) {
 this.base = eXcell_dhxCalendar;
 this.base(cell);
 this.edit = function(){}
}
eXcell_datero.prototype = new eXcell_dhxCalendar;

var my_layout = new dhtmlXLayoutObject('my_layout', '2U', 'dhx_terrace');
a = my_layout.cells("a");
b = my_layout.cells("b");
mygrid = b.attachGrid();
mygrid.setHeader("Date, Numero, Code");
mygrid.attachHeader("#text_filter,#text_filter,#text_filter");
mygrid.setInitWidths("180,110,110");
mygrid.setColAlign("left,left,left");
mygrid.setColTypes("datero,ro,ro");
mygrid.setColSorting("date,str,str");
mygrid.setDateFormat("%d/%m/%Y", "%Y-%m-%d %H:%i:%s");
mygrid.enableLightMouseNavigation(true);
mygrid.setSkin("dhx_terrace");

mygrid.enableAutoWidth(true);
mygrid.init();

thanks

Unfortunately the issue cannot be reproduced locally.
Your exCell sorts well for us.
If issue still occurs for you - please, provide with a complete demo, where the issue can be reconstructed locally.