Error in SDK

[mark goldin]

I am working on implementing a combobox into an app.
Here are steps I am taking doing some testing.
I am typing a text into the control and moving focus out of it. Then I am
returning to the control by clicking on it. Then I type another text. If
the combo has dropdown data everything works as expected, but if the combo
has no data then as soon as I type first new character it fails in SDK
in the following code class ComboBoxAccImpl.as because of dataProvider
being null. I tried 4.5.1 and 4.10. Same. What's interesting is if I use a
plain combobox in the test I am not getting this error. I understand that
it is somewhere in the in-house implementation but I just can't comprehend
what's going on.
Any idea?

 case "caretChange":
            {
                var index:uint = IndexChangeEvent(event).newIndex;
                // childIDs are 1 based, a plus two offset is used because
the
                // first child is an edit field and not a list item
                var childID:uint = index + 2;

                Accessibility.sendEvent(master, 0,
                        AccConst.EVENT_OBJECT_VALUECHANGE);
                Accessibility.sendEvent(master, 1,
                        AccConst.EVENT_OBJECT_VALUECHANGE);
                // This event will fire for the opened and close combo box
                // normally this only fires on open comboboxes but it is
fired
                // for closed comboboxes to support screen readers
                *if (ComboBox(master).isDropDownOpen && index >=0 && index
< ComboBox(master).dataProvider.length) *
                {
                Accessibility.sendEvent(master, childID,
AccConst.EVENT_OBJECT_FOCUS);
                }

                break;
            }

Thanks