title: AppCompatActivity openOptionsMenu not working
body: <p>I updated my question, since I solved one part, but the tricky one is still pending :
  I have an <code>MainActivity extends AppCompatActivity</code> 
  with fragments
  I deleted the ActionBar and put a small height LinearLayout as follows. I want an ImageButton to open the OptionsMenu. when the <code>onClick</code> is called, why the <code>openOptionsMenu();</code> is not called. I mean the Options Menu does not appear.
  While it does appear when I click on the Menu hardware button of the emulator.</p>
  
  <p>Thanks for your kind help
  below, find relevent part of the code</p>
  
  <pre><code>&lt;?xml version="1.0" encoding="utf-8"?&gt;
  </code></pre>
  
  <p></p>
  
  <pre><code>&lt;LinearLayout
      android:orientation="vertical"
      android:layout_width="match_parent"
      android:layout_height="match_parent"&gt;
  
      &lt;LinearLayout
          android:orientation="horizontal"
          android:layout_width="match_parent"
          android:layout_height="24dp"
          android:clickable="false"
          android:weightSum="1" &gt;
  
          &lt;TextView
                  android:text="@string/tx_notdone"
                  android:layout_width="wrap_content"
                  android:layout_height="match_parent"
                  android:id="@+id/tv_progress"
                  android:layout_weight="0.4" /&gt;
  
              &lt;ProgressBar
                  style="@style/Widget.AppCompat.ProgressBar.Horizontal"
                  android:layout_width="139dp"
                  android:layout_height="match_parent"
                  android:id="@+id/pb_simulation"
                  android:layout_weight="0.5"
                  android:max="100" /&gt;
  
              &lt;ImageButton
                  android:layout_width="wrap_content"
                  android:layout_height="match_parent"
                  app:srcCompat="@android:drawable/ic_menu_manage"
                  android:id="@+id/btmenuImg"
                  android:layout_weight="0.1"/&gt;
  
      &lt;/LinearLayout&gt;
      &lt;android.support.v4.view.ViewPager
          android:id="@+id/container"
          android:layout_width="match_parent"
          android:layout_height="match_parent"
          app:layout_behavior="@string/appbar_scrolling_view_behavior" /&gt;
  &lt;/LinearLayout&gt;
  
  &lt;android.support.design.widget.FloatingActionButton
      android:id="@+id/fab"
      android:layout_width="wrap_content"
      android:layout_height="wrap_content"
      android:layout_gravity="end|bottom"
      android:layout_margin="@dimen/fab_margin"
      app:srcCompat="@android:drawable/ic_dialog_email" /&gt;
  </code></pre>
  
  <p></p>
  
  <pre><code>ImageButton imgbtmenu = (ImageButton) findViewById(R.id.btmenuImg);
      imgbtmenu.setOnClickListener(new View.OnClickListener() {
          @Override
          public void onClick(View view) {
              Toast.makeText(getApplicationContext(), "click", Toast.LENGTH_SHORT).show();
              openOptionsMenu();
          }
      });
  </code></pre>
  
  <p>... </p>
  
  <pre><code>   @Override
  public boolean onCreateOptionsMenu(Menu menu) {
      // Inflate the menu; this adds items to the action bar if it is present.
      getMenuInflater().inflate(R.menu.menu_main, menu);
      return true;
  }
  
  @Override
  public boolean onOptionsItemSelected(MenuItem item) {
      // Handle action bar item clicks here. The action bar will
      // automatically handle clicks on the Home/Up button, so long
      // as you specify a parent activity in AndroidManifest.xml.
      int id = item.getItemId();
  
      //noinspection SimplifiableIfStatement
      if (id == R.id.action_settings) {
          // debug
          Toast.makeText(getApplicationContext(), "settings", Toast.LENGTH_SHORT).show();
          return true;
      }
      if (id == R.id.action_saveparam) {
          saveparam();
          return true;
      }
      if (id == R.id.action_loadparam) {
          // debug
          loadparam();
          return true;
      }
  
      return super.onOptionsItemSelected(item);
  }
  
  
  
  
  android {
  compileSdkVersion 23
  buildToolsVersion "25.0.2"
  defaultConfig {
  
      minSdkVersion 13
      targetSdkVersion 23
  
  
  
  dependencies {
  compile fileTree(dir: 'libs', include: ['*.jar'])
  androidTestCompile('com.android.support.test.espresso:espresso-core:2.2.2', {
      exclude group: 'com.android.support', module: 'support-annotations'
  })
  compile 'com.android.support:appcompat-v7:23.4.0'
  compile 'com.android.support:design:23.4.0'
  testCompile 'junit:junit:4.12'
  compile project(path: ':MPChartLib')
  </code></pre>
  
  <p>}</p>
  
  <p>I also found something describing a bug
  <a href="https://code.google.com/p/android/issues/detail?id=185217" rel="nofollow noreferrer" title="Issue 185217: openOptionsMenu&#40;&#41; does not show menu when inheriting from AppCompatActivity">Issue 185217:  openOptionsMenu() does not show menu when inheriting from AppCompatActivity</a></p>
  
  <p>Tried </p>
  
  <pre><code>    @Override
  public void openOptionsMenu() {
      // Based loosely on http://androidxref.com/6.0.1_r10/xref/frameworks/support/v7/appcompat/src/android/support/v7/internal/app/WindowDecorActionBar.java#getDecorToolbar
      final Window window = getWindow();
      final View decor = window.getDecorView();
      final View view = decor.findViewById(R.id.action_bar);
      if (view instanceof Toolbar) {
          final Toolbar toolbar = (Toolbar) view;
          toolbar.showOverflowMenu();
      }
  }
  </code></pre>
  
  <p>but it doesn't work.
  The Fabric button works fine and also another button on the fragment.
  The fragment implements a onTouch method (that works fine) to interact with an image that it displays.</p>
  
  <p>Thanks</p>