[Bug] [JS] Make Sales Order breaks with Custom Fields

[vjFaLk]

On Frappe (Latest Dev) + ERPNext (Latest Dev) + Custom Fields + Property Setters

Uncaught TypeError: Cannot read property 'map' of undefined
    at Class.get_selected (http://erpdev.com/assets/js/form.min.js:267:513)
    at http://erpdev.com/assets/js/form.min.js:183:178
    at Array.forEach (native)
    at _f.Frm.get_selected (http://erpdev.com/assets/js/form.min.js:183:109)
    at Object.open_mapped_doc (http://erpdev.com/assets/js/desk.min.js:610:159)
    at HTMLButtonElement.cur_frm.cscript.Make Sales Order (eval at setup (http://erpdev.com/assets/js/form.min.js:258:109), <anonymous>:830:15)
    at HTMLButtonElement.dispatch (http://erpdev.com/assets/frappe/js/lib/jquery/jquery.min.js:3:7537)
    at HTMLButtonElement.$event.dispatch (http://erpdev.com/assets/js/report.min.js:211:18)
    at HTMLButtonElement.r.handle (http://erpdev.com/assets/frappe/js/lib/jquery/jquery.min.js:3:5620)

Works perfectly on current stable branches with Custom Fields and Property Setters