deletion of an element like item, trigger, host, map, media type, user media etc that is used elsewhere happens without a warning.
specific example with triggers in maps :
when a trigger that is used in a map is deleted, that happens without a warning.
instead, when a trigger is deleted, a warning should be shown, if the trigger is :
a) an element in a map;
b) a link status indicator in a map.
warning should provide links to all maps that refer to this trigger.
same should happen when deleting an item that is used in a graph, map that is included in another map, media type that is used for some user media, user media and user that is used in action as a target...