Just wanted to thank you for sharing this little piece of code, which helped me solved my own problem:
I wanted to make the "Inside" position look and behave as an "After" position (including the preview line and all the rest).
In other words, to cancel having the Inside position and have only Before and After positions with a smooth transition between them (no gap).
Using your value override method did it!
I don't think I would have thought about it by myself otherwise... so thanks again for sharing.