Help with Conditional Display and Validation

Question

Version 4.1.1.00.23
Hello,
I'm having a difficult time with a conditional display and validation I'm hoping someone can help with.
Requirements:
When the Start Date (Datepicker) and/or End Date (Datepicker) change then display the Change Reason (Select List) and Change Description (Textbox)
If the page is saved without entering a Change Reason display a validation error message that the Change Reason cannot be empty (NULL)
What I've tried
Create a Dynamic Action on the Start Date
Event: Change
Selection Type:Item(s)
Items(s): P51_START_DATE
Condition: none
True Action Section:
Action: Show
Fire on Page Load: Checked
Show all page items on the same line: No
Affected Items Section:
Selection Type:Item(s)
Item(s): P51_CHANGE_REASON,P51_CHANGE_DESC
I've also created a Dynamic Action with similar settings for the P51_END_DATE.
I created a Validation for the P51_CHANGE_REASON as Function Returning Error Text:
DECLARE
    v_start_date    work_items.start_date%TYPE;
    v_end_date      work_items.end_date%TYPE;
BEGIN
    SELECT start_date
          ,end_date
    INTO   v_start_date
          ,v_end_date
    FROM   work_items
    WHERE  work_items_id = :P51_WORK_ITEMS_ID;
    IF ( (v_start_date != TO_DATE(:P51_START_DATE,'DD-MON-YYYY') OR v_end_date != TO_DATE(:P51_END_DATE,'DD-MON-YYYY') ) AND
          :P51_CHANGE_REASON IS NULL ) THEN
        RETURN 'Change Reason must have a value';
    END IF;
END;
The Issue
I tried to create another Dynamic Action to hide the P51_CHANGE_REASON and P51_CHANGE_DESC fields on page load, but when either of the date fields are changed and the validation is fired the P51_CHANGE_REASON and P51_CHANGE_DESC are hidden again.
There are two buttons to submit the page: 'SAVE' will submit the page and stay on the page and 'SAVE_CHANGES' will submit the page and branch to the previous page (which is a report with EDIT buttons to edit the record).
I can't get the page load Dynamic Action to NOT fire when the validation is fired.
I hope this is clear and if not what information can I provide?
Thanks,
Joe

Answer 1

Phil,
Thank you for looking at this.
Yes if the Change Reason is NULL when the edit page is displayed then the Change Reason and Change Description fields are hidden. If the Start Date (Datepicker) and/or End Date (Datepicker) change then display the Change Reason (Select List) and Change Description (Textbox). If the page is saved without entering a Change Reason display a validation error message that the Change Reason cannot be empty (NULL).
The problem I'm having is that if no Change Reason is entered and the page is saved thereby firing the validation the Change Reason and Change Description fields are hidden again (because of the On-Load Dynamic Action to hide them). So now the user can't put in a Change Reason...unless they change one of the date fields again which isn't going to be accepted.
Is there a way to determine if a validation error was fired and be able to use that on the On-Load Dynamic Action to hide the two fields? Something like...If the validation fired then don't run?
Please let me know if I'm still confusing you.
Thanks,
Joe