Hitting backspace in ASP.NET AJAX ComboBox causes JavaScript error

Question

I am using a ComboBox from the ASP.NET AJAX Toolkit (version for .NET 3.5) with values populated into its DataSource property.

If I use my mouse to drop the combobox down and select a value, then highlight the value and click backspace, I get an error:

Microsoft JScript runtime error: '_optionListItems[...].text' is null or not an object

My DropDownStyle is set to "DropDown" so I should be able to have text in the control that does not exactly match one of the items in it. Therefore, I do not understand why I get this error. It seems to work perfectly otherwise.

Answer 1

Per this forum post I had to edit the source code of the AJAX Control Toolkit. Once I added this additional condition, it all worked.