Web Custom Control & Custom Collection problem

[Donald_a]

I have a custom collection of complex types. The type is 'GraphValue' and the collection is 'GraphValueCollection'. On my Web Custom control I have a property 'GraphValues' which is a GraphValueCollection. I have it set up such that the whole thing works through Visual Studio's designer & the control works fine at runtime. However, as soon as i use the designer to add a GraphValue to the collection & build the project, the designer shows the default "Error creating control" dialog with the tooltip saying '' could not be set on property 'GraphValues'. The '' is not my fat fingers either - its 2 single quotes!! The control still works fine at runtime - but this is a very annoying problem. I'm using the attributes ParseChildren(true) and PersistChildren(false) on the custom control class I'm using the attributes PersistenceMode(PersistenceMode.InnerProperty), NotifyParentProperty(true) and DesignerSerializationVisibility(DesignerSerializationVisibility.Content) on the Property. The Property has both Get & Set accessors - I've seen a similar post where somebody solved the issue by removing the set accessor, but if i do this the IDE crashes!! Any help to solve this much appreciated. Thanks Donald