I was creating an example file for a bug in the Sphax MessageBox object and then an other bug appears in the Event Editor.
The set default button action don't work correctly.
(the first popup has default button 1, the second 2)
Only if I reset the whole settings it works.
Group bug in Event Editor
There is only one Group shown in the menus.
I don't know how this could happens (copy & paste).