jgGrid JS trying to show custom alert

Question

following this stackoverflow's solution suggest:

How to display custom alert boxes in custom_func of jqgrid

I was trying to make the same when opening form editor but using jqgrid js 5.6.0 and doing a sample it doesn't even get inside the custom_func part since those console.log doesn't fire in chrome:

jQuery(document).ready(function($){

    var useCustomDialog = false, oldInfoDialog = $.jgrid.info_dialog;
    
    $.extend($.jgrid,{
        info_dialog: function (caption, content, c_b, modalopt) {
            console.log('checking useCustomDialog: ' + useCustomDialog);
            if (useCustomDialog) {
                // display custom dialog
                console.log('getting custom dialog...');
                useCustomDialog = false;
                alert(content);
            } else {
                console.log('getting old dialog...');
                return oldInfoDialog.apply (this, arguments);
            }
        }
    });
    
    $("#test").jqGrid({
        shrinkToFit: false,
        forceFit: true,
        datatype: "json",
        url: '../myphp.php?op=1',
        editurl: '../myphp.php?op=2',
        colModel: [
            {
                label: 'ID',
                name: 'ID',
                width: 10,
                jsonmap: 'ID',
                key: true,
                editable: false,
                editrules : { 
                    required: true, 
                    edithidden: true 
                },
                hidden: true,
                editoptions:{ 
                    dataInit: function(element) { 
                        $(element).attr("readonly", "readonly"); 
                    } 
                }
            },
            {
                label: 'Field1',
                name: 'Field1',
                width: 300,
                jsonmap: 'Field1',
                editable: true,
                editrules : { 
                    required: true,
                    custom: true,
                    custom_func: function (val, nm, valref) {
                        console.log('tryig to get Field1 custom dialog here.... ' + val);
                        if ( isBlank(val) ) {                   
                            console.log('Field1 is empty');
                            useCustomDialog = true; // use custom info_dialog!
                            return [false, "Field1 is mandatory!"];                         
                        } 
                        else {
                            console.log('Field1 is not empty');
                            return [true];
                        }
                    } 
                },
                editoptions:{size:50}
            },
            {
                label : 'Field2',
                name: 'Field2',
                width: 300,
                jsonmap: 'Field2',
                editable: true,
                editrules : { 
                    required: true,
                    custom: true,
                    custom_func: function (val, nm, valref) {
                        console.log('tryig to get Field2 custom dialog here.... ' + val);
                        if ( isBlank(val) ) {   
                            console.log('Field2 is empty');
                            useCustomDialog = true; // use custom info_dialog!
                            return [false, "Field2 is mandatory!"];                         
                        } 
                        //else {
                        //  console.log('Field2 is not empty');
                        //  return [true];
                        //}
                    } 
                },
                editoptions:{size:50}
            },
        ],
        ondblClickRow: function(rowid) { 
            jQuery(this).jqGrid('editGridRow', 
                rowid,
                {   
                    editCaption: "Modify",
                    recreateForm:true,
                    dataheight: 500, 
                    height: 600, 
                    width: 680,
                    top: 40,
                    left: 170,              
                    closeOnEscape: true,
                    onclickSubmit : function (options, postdata) {
                        if( confirm('Save this record (Y/N)?') ) {
                            console.log( JSON.stringify(postdata) );
                            return {
                                returndata : JSON.stringify( postdata )
                            };
                        }
                    },
                    closeAfterEdit: true,
                    errorTextFormat: function (data) {
                        return 'Error: ' + data.responseText
                    }
                }
            ); 
        },
        sortname: 'Field1',     
        sortorder : 'asc',
        loadonce: true,
        viewrecords: true,
        height: 200,
        rowNum: 10,
        caption: "Test table",
        pager: "#testPager"
    }); 
    
    function isBlank(str) { return (!!!str || /^\s*$/.test(str)); }

    
}); 

maybe I forgot something to consider or even on jqGrid 5.6+ changed something about custom_func and firing custom alerts? Thanks in advance to all! Cheers! :-)