There is a difference between closing the window when things went well (usually a button at the lower or upper right) and when we just close the dialog (the x in the upper corner). When things went well and we close the window we should auto-refresh
The google search it came from: https://www.google.com/search?rls=com.microsoft:en-US:IE-Address&q=SP.UI.ModalDialog.showModalDialog+auto+refresh&spell=1&sa=X&ved=0ahUKEwjmsoLB6qHdAhVk3IMKHe64DXQQBQgkKAA&biw=1920&bih=934
This guy goes further so you can pass a “success” (1) or “just close” (0) back to the parent window/callback function that we don’t have yet. http://sharepointerz.blogspot.com/2012/04/sharepoint-modal-dialog.html
Here is another good article w. pics and everything for SP 2013.
That is also something that needs to be taken care of. So … the button we don’t have yet should appear on the main page when “successful” message is given and it should be a greenish color – other wise we leave ONLY the x in the upper right that is already there and no refresh needs to be done. What this new button triggers!? We need to a little more research.