ComboBox with textWidth unchanged whatever the TextFormat Style applied

Hi everybody,
I’m trying to autosize my combobox, according to the textWidth of its biggest items. I’ve got the right textWidth without setting the textFormat, but by setting textFormat, with a bigger font size (like 30), the textWidth stays the same !


var myFormat : TextFormat = new TextFormat("Trebuchet MS", 30, 0x0000FF);var myCbx
myCbx= new ComboBox  ;
myCbx.x = 0;
myCbx.y = 0;
myCbx.textField.setStyle("textFormat",myFormat);
myCbx.textField.setStyle("embedFonts",true);
myCbx.dropdown.setRendererStyle("textFormat",myFormat);
myCbx.dropdown.setStyle("embedFonts",true);

myCbx.addItem({label:"one"});
myCbx.addItem({label:"one more"});

this.addChild(myCbx);

for (var m:uint = 0 ; m < myCbx.length ; m++) {
  myCbx.selectedIndex = m;
  myCbx.drawNow();
  trace(myCbx.textField.textWidth);  // here is my trace, unchanged whatever the font size applied to my comboxbox
}

Any idea ?
Thanks