To reproduce: Follow this article http://www.telerik.com/help/winforms/propertygrid-features-custom-grouping.html . You will notice that the CustomGrouping event will not fire.
The code from the article does not work because PropertyGridItem does not have a "Type" property which is passed in the GroupDescriptor constructor: C# GroupDescriptor descriptor = new GroupDescriptor("Type"); VB Dim descriptor As New GroupDescriptor("Type") In order for the code to work one has to use one of the following properties: "Name", "Value", "Category", FormattedValue", "Label", "Description", "OriginalValue" or "SortOrder". We consider this to be an inconvenient way to perform grouping and we will improve our code so one would be able to group on any property of PropertyGridItem or derived types.