void addChildTab(Tab child){
  if (mChildren == null) {
    mChildren=new Vector<Tab>();
  }
  mChildren.add(child);
  child.setParent(this);
}

void addChildTab ( Tab child ) { if ( mChildren == null ) { mChildren = new Vector < Tab > ( ) ; } mChildren . add ( child ) ; child . setParent ( this ) ; }
when a tab is created through the content of another tab , then we associate the tabs .
