[importer] Primary Key dropdown opens on selecting Default field dropdown

When I click on primary key dropdown, everything works fine.
When I click on Default field dropdown by clicking on somewhere right side, again the primary key dropdown seems to be opens up. Although when I select the values, it goes to the default field only.
PFB the link to the video to reproduce the issue:
https://drive.google.com/a/cloudera.com/file/d/0B8-lOiYLBF2ZN3pBSEhwbnphRUk/view?usp=sharing