Requirement:
Trying unsuccessfully to create a journal entry workflow that once you click on a customized button (reject) a message will pop in case the user didn’t fill in the rejection reason field (customized field).
Solution:
Unfortunately, the Confirm Action does not work on Customized Buttons. This is because it uses the Before User Submit trigger. Which executes after a user clicks Save on a record.
You can check out this SuiteAnswers article for more information about the Before User Submit trigger:
I would like to mention that there’s also an enhancement filed for this. This is logged and being tracked under Enhancement 355430 SuiteFlow > Confirm Action > Triggered from clicking on a Custom Button