son, you don't need to get the handle from the message box if you don't ever use it. And you might want to use uiwait() and make it modal, rather than the way you and the others did it, so that it waits for the user to click OK before blasting onwards, executing subsequent code before the users have even had a chance to click OK yet.
message = sprintf('You clicked on button #%d,\nwhich set a = %f', choice, a);
Alternatively you can use helpdlg() instead of msgbox() if you want an "text balloon" displayed or warndlg() if you want an exclamation point displayed.
Hope this helps. Vote for my answer if it was helpful additional information.