Drag and Drop Content Type builder often wipes out fields

[M-Pixel]

Often, while using the drag-and-drop model editor, trying to place a field will destroy all previous fields. Once this happens, I need to hit cancel and lose all of the progress I made since the last save. I haven't found any consistent triggers for this behavior, but it happens very often. Here is a screencast showing the problem. There are no errors in the console when this happens.

[snide]

Thanks for the video.