Combo box crashs Internet Explorer

To reproduce this error just set the ItemCount to 0 in examples/quickref/combo.htm and click/dblclick several times the drop-down icon right-aligned.
I'm using IEx 6.0.2900.2180.xpsp_sp2_gdr.050301-1519

obj.setItemCount(0);

:-(

I will try to find a workaround.