I've handled OnClientItemsRequesting for radComboBox. Below is the handler code.
(sender._cachedText != unescape(sender._callbacktext))
I'm clearing out all items from the combobox before callback if the search text has changed since last callback.
sender._cachedText gives current value entered for search in combobox
sender._callbacktext gives last callback value.
I get the intended behavior in IE all versions.Whne user changes searchtext, items are cleared (as both the text are different). When user clicks on More Results box, the items are not cleared (as both the text are same)
When in Firefox, sender._cachedText is always empty. Cant figure out why.