title: can't find the fragment by tag
body: <p>Here is my code ... i cant find the fragment by tag </p>
  
  <pre><code> transaction = getFragmentManager();
          transaction.beginTransaction()
                  .replace(R.id.container,tachoFrag,"m1");
          transaction.beginTransaction()
                  .replace(R.id.container,overviewFrag,"m2");
          transaction.beginTransaction()
                  .replace(R.id.container,dataLogFrag,"m3")
                  .commit();
  
          tachoFrag = (menu1_Fragment) getFragmentManager().findFragmentByTag("m1");
          overviewFrag = (menu2_Fragment) getFragmentManager().findFragmentByTag("m2");
          dataLogFrag = (menu3_Fragment) getFragmentManager().findFragmentByTag("m3");
  
  
          if (D) Log.i(TAG, "run() -&gt; LogicAnalizerView - transaction.replace(R.id.container, tachoFrag)");
          if (tachoFrag != null &amp;&amp; tachoFrag.isVisible())
          {
              tachoFrag.setRevs(revs);
              tachoFrag.setSpeed(speed);
              tachoFrag.setFuelGauge(fuel);
              if(engTemp&gt;60)
              {
                  tachoFrag.setEngTemp(engTemp);
              }
              else
              {
                  engTemp = 60;
                  tachoFrag.setEngTemp(engTemp);
              }
              tachoFrag.setMileage(mileage);
              tachoFrag.setAmbientTemp(ambientTemp);
              tachoFrag.setGear(gear);
  
              transaction.beginTransaction().replace(R.id.container, tachoFrag,"m1");
              transaction.beginTransaction().commit();
         }
  
         ...
  
          if (D) Log.i(TAG, "run() -&gt; LogicAnalizerView - transaction.replace(R.id.container, dataLogFrag)");
  
              dataLogFrag.setData(time, speed, revs, gear);
  
              transaction.beginTransaction().replace(R.id.container, dataLogFrag,"Data logger");
              transaction.beginTransaction().commit();
  </code></pre>
  
  <p>when i added the replace transaction to add a tag the second replace for the overviewfrag cause a null pointer issue ... please help</p>