[ALOY-785] Pass TabGroup as __parentSymbol to widgets providing a tab

In the following code the widget providing the tab gets no reference to the TabGroup. Because of this, it cannot change the TabGroup's activeTab, ActionBar or perform other context-aware actions. *views/index.xml*

<Alloy>
  <TabGroup>
    <Widget src="myTab" />
  </TabGroup>
</Alloy>

*widgets/myTab/views/widget.xml*

<Alloy>
  <Tab>
    <Window />
  </Tab>
</Alloy>

Solution

This could easily be solved by having Alloy pass the TabGroup via the __parentSymbol property also found in other places where a widget is used. IMHO this property should/could *always* be passed to widgets/required controllers.

Notes

* Any workaround requiring code in the index-controller is not honoring the fact that widgets should be self-sustained. * Having said the above, even assign the TabGroup to Alloy.Globals. won't work since the tabs will be created before the controller code is executed.