Long WebListBox many columns

I have a WebListBox that sometimes has 200 rows and each row has 7 columns. This is slow in showing. I am building a new window and this listbox before showing. I have seen discussions in old treads about defect corrections to avoid refreshes (or delay a little) while the listbox is being built. Does that apply here at all, or is the problem somewhere else.

How slow ? Half a second, one second ? More ?