Modding Events
Event properties
allow_multiple_instances = [yes/no]: This will allow multiple instances of the same event to fire to one country.
fire_only_once = [yes/no]: if yes, the event will fire only once in a game. Normal events will fire whenever their conditions are met, this event will only fire once under any circumstance.
is_triggered_only = [yes/no]: if yes, then event may only be triggered by another trigger, decision, or through the game's programming. This also means you shouldn't include a trigger = { ... } parameter to your event, as it will be ignored. The only exception is with events triggered by the game's native-code, such as on-action election events.)
major = yes: Major events appear in a special window (with the country's flags by the title bar, and without a picture). This also means the event appears on the notifications, similar to how decisions do, with the prefix "Major Event".
immediate = { (effects) }: The game executes effects inside the immediate block the moment the event is fired before the option is selected by the player/AI.