I have a terrible problem in my WPF application that causes crashes when a user selects items in a ListBox control. I get a System.ArgumentException stating that 'An item with the same key has already been added'. According to the stack trace, this is occurring in the constructor of the 'System.Windows.Controls.Primitives.Selector.InternalSelectedItemsStorage'class.
You can see the full details of this problem by referring to the 'An item with the same key has already been added' Exception on selecting a ListBoxItem from code post that I added to StackOverflow. Please forgive me for not re-adding everything here, but there is a lot of information in the post.
How do I fix a problem that is occurring in code that is external to my application?