Is there a way of triggering a rule based on a calculation? For example if a the difference between two dates is greater than 30 days? I know this can be done in the Validation Settings for the list, but I’d like the message to appear when the end date changes rather than when the user attempts to save the record.
Currently you can do this calculation with [today] by comparing with [today]+30 (not currently documented), but not when comparing two date columns. I will however add this to the next release – BETA hopefully later tonight.