strange problem.. remove()append options to listbox is not visible on screen until I mouse over the listbox.. .?

strange problem.. remove()append options to listbox is not visible on screen until I mouse over the listbox.. .?

Internet explorer 8
windows 7
classic asp page
 
problem does not exist in firefox.
 
when i do a remove().append to add options.. I cannot see my changes until i run mouse over the listbox??
 
thanks