Exit program not asking to save project?

Perhaps this bug has already been addressed.. but it appears that if you close the main TGB editor window, the appl closes even if unsaved changes to the project exists... it really should prompt the user to save before exitting.. I lost some work on the fish tutorial this way when I accidently closed the window while running the program. I thought the X would just stop the play but bring you back to the editor..

Upon restart.. the previous work was not saved.