title: ionic back button not taking me to the previous page when I jump from tab1's child page to tab2's child page
body: <p>I have tabs, where each tab is its own page/path.
  So there exists tab1-&gt;childComponent1 and tab2-&gt; childComponent2.
  Now I performed a navigation using</p>
  <pre><code>navCtrl.navigateForward(['tab1/', 'childComponent2/'])
  </code></pre>
  <p>The childComponent2 has a back button.</p>
  <pre><code>&lt;ion-back-button class=&quot;back-button&quot; text=&quot;&quot; defaultHref=&quot;&quot; icon=&quot;arrow-back&quot;&gt;&lt;/ion-back-button&gt;
  </code></pre>
  <p>This takes me back to the defaultHref, which is an entirely new tab. I'm guessing it's utilizing the defaultHref because navController doesn't have an empty stack with no navigation history in it.</p>
  <p>So what I was looking for is the following.</p>
  <p>SCENARIO 1 - childComponent1 -&gt; childComponent2 ... On clicking ionic-back-button here it takes me back to childComponent1</p>
  <p>SCENARIO 2 - tab2 -&gt; childComponent1 .. on clicking ionic-back-button here it takes me back to tab2</p>
  <p>SCENARIO 2 Seems to be working perfectly alright at this point.</p>