Ensure that you set the DesignerSerializationVisibility attribute with a setting of DesignerSerializationVisibility.Content on your collection property.

 I have a collection class that is derived from CollectionBase. There is a property on my *Form Class* of type= MyCollection class. This form property has the following attributes:

 <Editor(GetType(System.ComponentModel.Design.CollectionEditor), GetType(System.Drawing.Design.UITypeEditor)), DesignerSerializationVisibility(DesignerSerializationVisibility.Content)> _

 Public Property Parameters() As UIWinScreenParametersCollection

 At deign-time VS.Net displays the collection editor and allow us to input new items but items are not getting presisted. Is there any other attribute I have to use please ?

 Thanks