Android – onprepareoptionsmenu copies items in the actionbar

When I use onprepareoptionsmenu to add a menu item, the menu item will copy itself in the action bar. I am using the clip and creating an initial menu in the action bar of the main activity, as shown below:

...
 @Override
    public boolean onCreateOptionsMenu(Menu paramMenu) {
    super.onCreateOptionsMenu(paramMenu);
    paramMenu.add(0, 1, 0, "DashBoard").setIcon(R.drawable.ic_dashboard)
        .setShowAsAction(1);
    return true;
    }

Then I add another item to one of the clips as follows:

...
@Override
    public void onPrepareOptionsMenu(Menu paramMenu) {
    paramMenu.add(0, 2, 1, "FullScreen").setIcon(R.drawable.ic_fullscreen)
        .setShowAsAction(1);
    }

For some reason, items added through the fragment class are displayed twice... What's wrong with me?

Any help for my mistake will be greatly appreciated

resolvent:

This item may be displayed twice because you want to add it twice. See docs for onprepareoptionsmenu:

I really won't blindly add an item in onprepareoptionsmenu. You should check whether it has been added first