What are you doing?
Using a RadComboBox, I'm hiding items from the user view under certain conditions.
What's the problem?
The combo items hide perfectly, however, when I click the combo box and then click anywhere else on the page (in other words, loose focus after focusing on the combobox) all the items I have hidden become visible again.
What else have you tried?
Thinking maybe I am not using the Telerik RadCombo Client Side API correctly, I decided to check whether deleted or disabled items would also magically re-appear when focusing and unfocusing from the RadComboBox.
The result; this issue only happens when hiding items, not when deleting or disabling RadComboBox items.
Demo of problem
For clarity and convenience, I've setup a page which very simply demonstrates the problem. Download TestRadComboItemHide.zip and extract TestRadComboItemHide.aspx.
Place this ASPX into a website/webapp project and run ensuring you have telerik dll in the bin or Telerik installed on your dev computer.
Additional info
The work around to the problem is posted on the telerik forums. The solution was provided by another forum member, not Telerik.