Ionic NOT SUPPORT multiple tabs in a project?!

I am trying to do a hybrid app using ionic with the structure that look like this:

#/app                          (sidemenu.html)
#/app/noTabContent1   (notab-content1.html)
#/app/noTabContent2   (notab-content2.html)
#/app/tab1                  (tab1.html)
#/app/tab1/content1     (tab1-content1.html)
#/app/tab1/content2     (tab1-content2.html)
#/app/tab2                   (tab2.html)
#/app/tab2/content1    (tab2-content1.html)
#/app/tab2/content2    (tab2-content2.html)

The problem is that, it seems like conflict between the tab page. For example, if I first visit tab1 content page, then I go visit tab2 content page later on, it will still display tab1 content. If I visit tab2 content page first, it will always display tab2 content no matter how I try to access tab1 content page.

I have put my example code here ( http://codepen.io/anon/pen/LpVVOr?editors=101) for easier understanding. If you can’t see the problem, please try to refresh the page after testing one of the tab.

Why is it like that? Is my structure wrong? Or, it is ionic bug? How can I overcome it?

Thank you.