Although this is still in the "responsive" subject, the problem is relatively different here. So I moved your post to a new thread so it becomes focused on your specific inquire.
And for the feature you want, the closest I can think of it would be with Tab Panels, like illustrated in this example:
- Tab Panel > Basic > Advanced Tabs
But this is hardly a navigation bar. For this task, we have the Breadcrumb component. While it does not collapse into an icon, when space is not enough, the breadcrumb becomes scrollable. To see this aspect of the breadcrumb, just get the example below, transform the
and then open the example and resize the window to make it too narrow to fit the breadcrumb:
- Toolbar > Breadcrumb > Overview
You can see further documentation on the component in Sencha documentation page for Ext.toolbar.Breadcrumb
Hope this helps!