Validation not working when Issue is modified

Question

We have picklist field Action on which we have put a field validation which will ensure that depending on the Job title of the logged User, he will be able to select appropriate Action value.
The problem we are facing is : The validation is not triggered when an Issue is opened and saved without any changes to Action picklist.
for eg: If User 1 with Role A creates an Issue with Action values as per his Role. Now User 2 with Role B opens the Issue , he is displayed with the Action value saved by User 1. Now if User 2 changes the details of the Issue and doesn't change the Action, the Issue is saved. The validation doesn't work in this case, as Action is not modified.
Validation is as follows:
Left([<Action>],4) = Left(JobTitle(), 4) OR Left([<Action>],4) = IIf((JobTitle()="Manager" OR JobTitle()="Executive"),"Fact" ,"xxxx") OR Left([<Action>],4) = IIf(JobTitle()="Executive","Mana" ,"xxxx")
Also we cannot restrict users using Access control because, if we Restrict Issue modification by making Issues read-only for non owners , then Users cannot add related information like attachments and solutions.
Any ideas would be welcome in this regard.
Sandy

Answer 1

I have a similar situation that I had to create a workflow rule that is triggered "before a modified record has been saved" and the rule looks for a change on record like;
PRE('<ModifiedTimestamp>')<>[<ModifiedTimestamp>] AND PRE('<Action>')=[<Action>] this checks to see if the record has been modified but the Action hasn't.
Then you want to have the workflow rule "Update Value" of the "Action" field with the same value that it had at the beginning of the operation, like;
[<Action>] in the "Value" formula field and ensure the "overwrite existing values" check box is selected.
In essence you're sending the same value to the "Action" field but it will trigger the Validation rules each time there is any change on the record.
Let me know if you have questions...
Dan