TextArea font does not change (for editing) if its blank

I have a text field (flash.display.textField) for editing, but the default font does not change unless I put some data there e.g. with AppendText() or .Text=""

private var editarea:TextField
editarea.setTextFormat(FontFormat);
editarea.appendText (""); // = " "; // font stays wrong if blank
editarea.setTextFormat(FontFormat);

From stackoverflow

• editarea.defaultTextFormat = FontFormat;