title: Change decimal seperator of GXT Numberfield to comma
body: <p>Is it possible to change the decimal seperator of GXT Numberfield from point to comma? I searched and tried a lot, but can't find a solution.</p>
  
  <p>When filling the form field of type "FloatField" with a number like 67,8 - the value of the field is switched to 67.8. So the field accecpts inputs with commas, but the NumberFormat to display it, is simply wrong.
  How can i change that?</p>
  
  <p>Thanks in advance, David.</p>