Actionscript 2.0 :: V2 ComboBox Not Showing Current Selection?

I am building a website for an online store in Flash 8. I needed to use a dropdown menu for selecting the size of a clothing item, so I just used the default ComboBox component. I thought it was working fine, until I came across a strange bug (with the component, or my own code) where the ComboBox was not showing the current selected item.

The dropdown's list works, and shows all the options, but if you click on one, it doesn't get displayed as the current selection in its TextBox. The weird thing is that it still works fine, and I can access the data ok. If I use myComboBox.text I can access the current selections text, even though Nothing is being displayed.

Has anyone come across this before, and has any suggestions for what I am doing wrong.

A few details: Here is the actual code I am using to load the options into the ComboBox: Code: Select allvar my_cb:ComboBox = this.pages.product.size_comboBox;
my_cb.removeAll();

var sizesList:Object = productData[categoryID][productID]["sizes"];
for(var s in sizesList){
my_cb.addItem({data:s, label:sizesList[s]});
}
my_cb.redraw();

There are a number of other things happening the same time as its adding the items to the comboBox, e.g. loading images, creating movieClips, etc. Could loading this be causing the comboBox to not function properly.