How to reproduce : 

1/ On _admin, select an existing SCC and click on "Update" button. 

2/ Configuration form of this SCC is opened. Change one or two attributes value. 

3/ Click on cross to close the SCC configuration form (without saving updates)

=> Configuration form is closed without asking any question. 

(Since some updates have been performed , a question "Do you want to save your changes ?" shall be present.