How to resolve the textbox focus issue of find and replace dialog in RichTextEditor while using inside jQuery mobile Popup?

<div data-role="main" class="ui-content">
        <a href="#myPopup" data-rel="popup" class="ui-btn ui-btn-inline ui-corner-all" data-container="#mypopup">Show Popup</a>
        @{List<String> toolsList = new List<string>() { "edit" };
            List<String> edit = new List<String>() { "findAndReplace" };
        }
        <div data-role="popup" id="myPopup" style="height:800px;">
 
            @{Html.EJ().RTE("rteSample").ShowHtmlSource(true).Width("100%").ContentTemplate(@<div>
        <p><b>Description:</b></p>
        &lt;p&gt;The Rich Text Editor (RTE) control is an easy to render in
        client side. Customer easy to edit the contents and get the HTML content for
        the displayed content. A rich text editor control provides users with a toolbar
        that helps them to apply rich text formats to the text entered in the text
        area. &lt;/p&gt;
        &lt;p&gt;&lt;b&gt;Functional
        Specifications/Requirements:&lt;/b&gt;&lt;/p&gt;
        &lt;ol&gt;&lt;li&gt;&lt;p&gt;Provide
        the tool bar support, it’s also customizable.&lt;/p&gt;&lt;/li&gt;&lt;li&gt;&lt;p&gt;Options
        to get the HTML elements with styles.&lt;/p&gt;&lt;/li&gt;&lt;li&gt;&lt;p&gt;Support
        to insert image from a defined path.&lt;/p&gt;&lt;/li&gt;&lt;li&gt;&lt;p&gt;Footer
        elements and styles(tag / Element information , Action button (Upload, Cancel))&lt;/p&gt;&lt;/li&gt;&lt;li&gt;&lt;p&gt;Re-size
        the editor support. &lt;/p&gt;&lt;/li&gt;&lt;li&gt;&lt;p&gt;Provide
        efficient public methods and client side events.&lt;/p&gt;&lt;/li&gt;&lt;li&gt;&lt;p&gt;Keyboard
        navigation support.&lt;/p&gt;&lt;/li&gt;&lt;/ol&gt;
    </div>).ShowFooter(true).MinWidth("200px").Width("500px").ToolsList(toolsList).Tools(tool => tool.Edit(edit)).Render();}
        </div>
    </div>
</div>
 
<script>
            ej.RTE.prototype._renderFindandReplaceDialog = ej.RTE.prototype._renderFindDialog;
 
            ej.RTE.prototype._renderFindDialog = function (target) {
                this._renderFindandReplaceDialog(target);
                this._findDialog.setModel({ 'containment': '#rteSample_wrapper' });
            }
 
</script>