Trigger when child table is populated by system-code

ERPNext Customize ERPNext
1

Hi
I am trying to load additional custom-fields in each row of the “items” table
on Sales Invoice. The documented triggers work when adding rows manually by
selecting “Add row”. However , these triggers are not fired when using the “Get Items FRom” button which caused the table to be populated by the system.

frappe.ui.form.on('Sales Invoice', {
	refresh(frm) {
		// your code here
	},
	items_add: function(frm) {
	    frappe.show_alert("Table");
	}
});

frappe.ui.form.on('Sales Invoice Item', {
	items_add: function(frm) {
	    frappe.show_alert("Table");
	},
	items_on_form_rendered: function(frm) {
	    frappe.showa_alert("REndered");
	}
});


frappe.ui.form.on('Sales Invoice', {
    refresh: function(frm) {
        if (frm.doc.items && frm.doc.items.length > 0) {
            frm.doc.items.forEach(function(item) {
                frappe.show_alert("Table");
            });
            frm.refresh_field('items'); // Ensure UI updates
        }
    },
    onload_post_render: function(frm) {
        frappe.show_alert("Post render");
    }
});

Could anyone assist please ?