Header is not updated in HeaderedContentControl when dynamically change the item using TreeView

_This issue has been moved from [a ticket on Developer Community](https://developercommunity2.visualstudio.com/t/Header-is-not-updated-in-HeaderedContent/875973)._

---

I test this on .Net 4.6

It seems like when you change the selected item in TreeView, the corresponding HeaderedContentControl tag might not be updated-- instead, it is being erased.

I attach the complete small example here.

The important thing to note is that if I change the second Item from type ViewModel2 to ViewModel, then the header is updated properly. I've no idea why this is the case, that ViewModel2 type fails to work but ViewModel works, after all, ViewModel2 is a subclass of ViewModel and has no extra content.

---
### Original Comments

#### Feedback Bot on 1/7/2020, 10:49 AM:

We have directed your feedback to the appropriate engineering team for further evaluation. The team will review the feedback and notify you about the next steps.

#### Feedback Bot on 2/14/2020, 05:01 PM:

I have detected that for the last 35 days, this issue didn't have much product team activity and a very small amount of new votes or comments. Based on this, its severity, and affected area, it’s my experience that this issue is very unlikely to be fixed.

---
### Original Solutions
(no solutions)