Hi,
Sometimes, an FSM will work fine (correctly send an event), but when I open up the state to view the Send Event action, the Event field will suddenly appear blank (even though it is previously set) and suddenly PM throws the "blank required field" error. If I attempt to re-select the Event from the list, the Global Event that I want to send to will not even appear in the list any more! I have to go to the FSM that contains the Global Events, then "look at" the Events list on that FSM... then, when I go back to the Send Event action, those Global Events that I "looked at" are suddenly visible again and able to be chosen (and usually, the one is was previously set to will appear to be set again).
In this case the FSM sending the event is attached to a prefab (though I am editing it as an instance, not from the Prefabs list), but it is not a template, and it is not referring to any specific object (it is set to Broadcast All in this case).
I am getting more and more of these mysterious "Things are disappearing" type of bugs (see my previous thread,
http://hutonggames.com/playmakerforum/index.php?topic=3861.0 ) as the number of FSM's, global variables, and global events increases in my project to many hundreds of each.
Although the bug happens all the time inside different FSM's, it is not strictly reproducible because the events re-appear after looking at them and there is nothing specific I can do to get them to disappear again - it just seems to happen randomly.