Hi,
See this Wayne reply for a similar question about the startup screen property.
@support-wayne wrote:
This is a warning that is now displayed for screens that have the “startup screen” property enabled see http://www.genuitec.com/mobile/docs/highlights/current/#sec10
The change was introduced to support upcoming features where the single startup screen in your project is clearly designated. An additional change in ver 2.2 is all new design files are created with the startup screen property disabled. We encourage developers to begin adjusting their UI designs by disabling the startup screen property of all non-startup screens.
http://www.genuitec.com/support-genuitec/viewtopic.php?f=8&t=3735
As you can see, is the oposite of your question, so you should enable this property in your startup screen.