<p dir="auto">Both <strong>.dropdown-menu</strong> and <strong>.navbar</strong> have same z-index:1000 so navbar overriding dropdown menus.</p>
<p dir="auto">Example:<br>
<a href="http://getbootstrap.com/examples/theme/" rel="nofollow">http://getbootstrap.com/examples/theme/</a><br>
Just click to first navbar's dropdown menu in Navbars section.</p>
<p dir="auto">In the example at <a href="http://getbootstrap.com/examples/theme/" rel="nofollow">http://getbootstrap.com/examples/theme/</a><br>
<a target="_blank" rel="noopener noreferrer nofollow" href="https://camo.githubusercontent.com/73a849eaa4ec901b31e0f5b56444818ad93a4f2e33c8c22e55625a53145de11c/68747470733a2f2f662e636c6f75642e6769746875622e636f6d2f6173736574732f353139333839322f3938393930322f31623534643035652d303931652d313165332d383335662d3566363663386330393136362e706e67"><img src="https://camo.githubusercontent.com/73a849eaa4ec901b31e0f5b56444818ad93a4f2e33c8c22e55625a53145de11c/68747470733a2f2f662e636c6f75642e6769746875622e636f6d2f6173736574732f353139333839322f3938393930322f31623534643035652d303931652d313165332d383335662d3566363663386330393136362e706e67" alt="screen shot 2013-08-19 at 5 22 34 pm" data-canonical-src="https://f.cloud.github.com/assets/5193892/989902/1b54d05e-091e-11e3-835f-5f66c8c09166.png" style="max-width: 100%;"></a> the dropdown appears below the other menu.</p>
<p dir="auto">Firefox 23.0.1</p>