Issue with combobox popup during orientation change

<combobox>
    <comboitem label="Item 1"/>
    <comboitem label="Item 2"/>
    <comboitem label="Item 3"/>
</combobox>

zk.afterLoad('zul.inp,zkmax', function() {
    // WORKAROUND for orientation change issue
    if (zk.ios) {
        window.addEventListener('orientationchange', function() {
            if (window._openCombobox) {
                window._openCombobox.close();
            }
        });
    };

    var xCombobox = {};
    zk.override(zul.inp.Combobox.prototype, xCombobox, {            
        
        open: function(opts) {
            xCombobox.open.apply(this, arguments);
            
            // WORKAROUND for orientation change issue
            if (zk.ios && this._open) {
                window._openCombobox = this;    
            }               
        },
        
        close: function(opts) {
            xCombobox.close.apply(this, arguments);
            
            // WORKAROUND for orientation change issue
            if (zk.ios && !this._open) {
                window._openCombobox = null;
            }
        }
    });
});