The other thread was a support ticket, started by William.
If you are also using RadListBox with thousands of items I suggest binging it to a DataView object. You can use the DataView to filter the data so that RadListBox does not have to create all those items. This approach is also valid for RadComboBox.
For Q2 2010 we will be providing a completely new RadListControl whose aim will be to replace the current list box and address all its issues while at the same time adding new features. The new list control will be able to bind to 150 000 data items in about a second.
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