In the URL 1, When I click and drag the container 1, It will disappears. Here are some of the screenshots and the URL ( Drag & Drop Lists for angular.js ) of it.
I was able to reproduce this issue on our end. I have written up a report and I have submitted it to the developers for further consideration. I have provided a link to the public tracker. Please feel free to use the link provided for future updates.
There is no target release for this issue on this time. Feel free to use the link for future updates. You will be able to find the target release version on the public tracker when there is one available.