Crash in timeline after "collapse thread"

[schmidt-fu]

Crash when scrolling to a certain post.

Steps to reproduce:

1. Open the latest post in timeline.
2. Open the menu on any of the posts in the thread
3. Chose "collapse thread" from the posts menu
4. Go back
5. Scroll down a bit until the posts is well outside view ( two screens worked)
6. Scroll up to the top
7. The app crashes before reaching the top. Stracktrace contains ClassCastException from a collapsed post view.

[33mhz]

I've been able to reproduce this within the thread view, but not in Global, unified, etc.