The user is not able to create an object in the assigned Blackboard, unless Blackboard is deleted, but instead created inside/through the Behavior Tree view.
Detailed video bug example
The bug outlined here Basics of AI | Live Training | Unreal Engine - YouTube
Delete Blackboard create inside/through the Behavior Tree view (see above video link).
For a fix see video link.
I am also looking for the same answer.Currently I think you have to open Blackboard and Behavior Tree both to prevent Editor from Crashing. By the way I am using UE4.8.6.
@unit23 oh sorry that video yeah I have seen that .The other fix is just create both things and open them both and then create object
I was able to reproduce this issue on our end. I have written up a report ( UE-21179) and I have submitted it to the developers for further consideration. I will provide updates with any pertinent information as it becomes available. Thank you for your time and information.
Make it a great day