Creator: None (system-internal Symbol).
This Tag is used to overwrite the idle message Elody will display if there are no Rules or Options eligible to be used under the current parameter settings.
To do so, create a Tag with this symbol targeting a hidden Message.
Target this Tag with a !nullify Tag to deactivate it again. The last non-nullified !set_idle_message will be the active one.
Note that this is related to !set_status_message:
!set_idle_message is a normal Message that is generated when the user needs to do something, and it remains visible after they do.
!set_status_message is not a real Message object but a dummy that is displayed at the bottom of the Scenario so long as there aren't any active Options to choose from.