#281 Remove/demote validation rule 21206

[Lucian Smith]

Validation rule 21206 was added in L2v4, but removed for L3v1. It states:

"If an <event>'s 'useValuesFromTriggerTime' attribute has the value 'false', then the <event> must contain a <delay> element. The implication of 'useValuesFromTriggerTime=false' is that there is a delay between the time of trigger and the time of value assignments performed by the <event>."</event></delay></event></event>

However, it is not the case that a delay must separate the triggering of an event and its execution: simultaneously-triggered events can (and do) change the state of the model, such that 'useValuesFromTriggerTime' can potentially always be relevant, even for events with no delay.

Now, it is true that you cannot guarantee the order that simultaneously-triggered events will execute. And relying on it to have a particular order seems like the only probable need to set 'useValuesFromTriggerTime' to be 'false'. So maybe it's OK to leave the validation rule here anyway. But if it's not removed, it seems like it might be a good idea to at least mention the simultaneous-events caveat?

[Frank Bergmann]

I accept the issue as valid, but i would vote for the least amount of changes for L2. So I would keep the rule.

[Sven Sahle]

I think it should not be changed for L2V5

[Lucian Smith]

From common consent at the 2015 HARMONY editor's meeting, we decided to not make this change, and leave the validation rule as it is.