If you see your JQuery-ui dialog being hidden by other elements in the webpage, then you need to increase its z-index. I recently ran into the case where the JQXgrid widget was using very high z-indeces outside of my control.

Here’s the code:

ZIndexer = function () {
    var self      = this;
    this.Elements = [];
    
    this.Add = function (JQuerySelector) {
        var DomElementArray = $(JQuerySelector)
        $.each(DomElementArray, function (i, element) { self.Elements.push(element) })
        return this;
    }

    this.GetNextFreeZIndex = function () {
        var zIndeces = $(this.Elements).sort(function descending(a, b) {
            var bZIndex = $(b).zIndex()
            var aZIndex = $(a).zIndex()
            return bZIndex - aZIndex
        })

        return $(zIndeces[0]).zIndex() + 1;
    }

}

//My grid is in a div with id jqxgrid. All of its child elements need
//to be considered when figuring out the next available ZIndex
var foo = new ZIndexer().Add("#jqxgrid *");

//Set the z-index of the jquery-ui dialog and its overlay to the highest available
$('.ui-widget-overlay').css('z-index',foo.GetNextFreeZIndex());
$('.ui-dialog').css('z-index',foo.GetNextFreeZIndex() + 1);