1.) Run Editor
2.) Create a custom structure
3.) Create a DataTable based off of that custom structure
4.) Open DataTable editor
5.) Add rows
6.) Close DataTable “window”
7.) Save and exit DataTable editor
8.) Open DataTable editor
9.) (At this point DataTable window is hidden) Add row
10.) CRASH
I was able to replicate the issue. I have logged a JIRA ticket with the developers for them to address this. You can access UE-52552 at anytime to check the status of the bug.