static/ext/src/ux/grid/menu/ListMenu.js
function () {
        var me = this;
        if (me.loadOnShow && !me.loaded && !me.store.loading) {
            me.store.load();
        }
        me.callParent();
    }
function () {
        var me = this;
        if (me.loadOnShow && !me.loaded && !me.store.loading) {
            me.store.load();
        }
        me.callParent();
    }
Lists will initially show a 'loading' item while the data is retrieved from the store.
In some cases the loaded data will result in a list that goes off the screen to the
right (as placement calculations were done with the loading item). This adapter will
allow show to be called with no arguments to show with the previous arguments and
thus recalculate the width and potentially hang the menu from the left.