Transition from private conversation back to contact list affects wrong item
I ran into a couple of problems while testing the transition between the contact list and the private conversation. Reproducing them requires API 23 as the transition is disabled on older versions.
The first problem occurs when the contact moves to a new position in the list while the private conversation is open. This can happen if you select any contact except the one at the top of the list, send a message, and return to the contact list. The contact will now be at the top of the list. The problem is that the reverse transition moves the avatar from the toolbar to the contact's old position in the list, which is now occupied by a different contact.
The second problem occurs when you remove the contact, which automatically returns you to the contact list. The transition moves the avatar from the toolbar to the contact's old position in the list, which may now be occupied by a different contact or may be empty.