Could you help me with MultiProperty implementation on EPi7. I've tried to do it just like on version 6R2 but with no luck. I'm getting 'Object reference not set to an instance of an object.' when trying to edit the property. This is the declaration:
[CultureSpecific]
[Editable(true)]
[Display(
Name = "test ",
Description = "test",
GroupName = SystemTabNames.Content,
Order = 100)]
[BackingType(typeof(PropertyTestCategories))]
public virtual TestCategories test { get; set; }