Through settings.ini it is possible to define behavior of the navigation's exit button.
Please note this setting is available since the release version 15e.
The variable is onBackBtn and is available in [RuntimeSettings] section.
The possible values are as follows
;onBackBtn=minimize | exitDialog | exitSilent | disable
The minimize option will put the navigation into background.
The disable option will disable exit key.
The exitDialog option will trigger the exit confirmation dialog.
The exitSilent option will exit silently.