Is there a way to add a Send Email action that will actually be triggered when the Approve button is clicked (using standard PO approval process - workflow)? Error message is: SENDEMAIL action skipped. Not executable with trigger BEFORELOAD

You can't send an email using the BeforeLoad trigger,,,, it should be either "Entry" or "AfterRecordSubmit"

I tried that already. But clicking the Approve button doesn't drive After Record Submit. Entry doesn't work either.

You have to do a transition to a new state upon execute of button Then on entry in the new state put the send email action

I have that transition but I can't select the button because it's a standard Approval button.

Oh i see.....so you don't have Approval Routing enabled for Purchase Orders?

Correct

That will be very difficult to manage.....The only think I can think of is you can try to create a transition based on the Status field changing to "Approved". And leave the trigger blank> THen put the send email action on entry in the new state....but I think you would run into the same issue...it's worth a try though

That's the first thing I tried actially. Transition based on status with no trigger. Same issue as you said. With saved search, it does allow us to attach the PO. I'll try hiding the standard approve button and create a custom one that ticks the Supervisor Approval checkbox in the PO.