Custom Message displaying issue in PR Account Generator

Hi Team,

We have done the customization of PR Account Generator and want to display the error message on the form if the code combination is invalid.

I have used the below code for the same and the error message is displaying when I click on the save button. But we need this error message when I click on the Charge Account tab . Can you please help me to resolve this issue.

Logic Used:

fnd_message.set_name ('FND', 'ERROR_MESSAGE');

FND_MESSAGE.set_token('MESSAGE','Exception at Expense Account');

wf_engine.setitemattrtext(itemtype      => itemtype,

                                      itemkey       => itemkey,

                                      aname         => 'ERROR_MESSAGE',