Yea, first paragraph...
You right, this is small addition, but large for me ( cause it my first trying )
Check ViewPorts - remember, the standart destroyOutsideLayout destroy objects, when they left out screen size values, my addon destroy, when object left any of viewPorts. (and as a "feature" this behaviour can be turned on/off, wich can't do official )
But, if you whant, you can delete this topic, I don't see that this needed to somebody