Bitrix24 business process - remove duplicates at the 2nd click of the save button?

Question

Bitrix24

Good afternoon, tell me how to solve the problem of duplicates when pressing the "save" button multiple times in the bitrix24 business process?

I wrote a business process for self-accounted vacation requests. Everything works, but when filling out the form, employees click the "Save" button several times. I can’t edit the save button action - this is a basic function. I tried to solve the problem in business process blocks at the very beginning, I inserted PHP code. When saving, a message immediately appears stating that there is an error in the PHP code. So if instead of an error the notification "Application saved" is triggered, users will no longer click the button again (unless they immediately click it with the 2nd click).

But I can’t display a window with a notification in the PHP code from the business process. Found what?? it is not necessary to write here: but without it all the same does not work. Also, in the examples there is no simple display of a window with a notification like alert or echo. How to write a notification to make it work?