Editable ComboBox content string clipping problem

All,

I create 2 combo boxes on a page: an editable one and a non-editable
one. Both of them have the same string items which are too long to
entirely fit into the combo box. E. g. the size of the combo boxes is
just large enough to display the half of the string "one word".
Now when selecting the item "one word" in both combo boxes, the
editable combo box would show "word" while the non-editable combo box
would show "one ".
I would like the editable combo box to show the first part of the
selected string item like the non-editable combo box does. Can anybody
help?

Thanks,
Michael