title: bootstrap button: Stretch to fill its container space
body: <p>I'm using bootstrap buttons, I would like to stretch the dropdown button in the middle to fill the rest of the toolbar space.</p>
  
  <p><img src="https://i.stack.imgur.com/tUVh6.png" alt="enter image description here"></p>
  
  <p>HTML (shortened code):</p>
  
  <pre><code>&lt;div class="gallery-toolbar"&gt;
      &lt;ul style="padding:0"&gt;
     &lt;li&gt;&lt;a&gt;Back&lt;/a&gt;&lt;/li&gt;
  
     &lt;li id="gallery_title"&gt;
     &lt;div class="btn-group"&gt;
       &lt;a class="btn btn-default"&gt;&lt;?php echo $gallery-&gt;title ?&gt;&lt;/a&gt;
       &lt;a class="btn btn-default dropdown-toggle" data-toggle="dropdown"&gt;&lt;span class="caret"&gt;&lt;/span&gt;&lt;/a&gt;
       &lt;ul class="dropdown-menu"&gt;some php&lt;/ul&gt;
     &lt;/div&gt;&lt;/li&gt;
  
    &lt;li&gt;&lt;a&gt;Slideshow&lt;/a&gt;&lt;/li&gt;
  </code></pre>
  
  <p>css:</p>
  
  <pre><code>.gallery-toolbar li { list-style:none; display: inline }
  .gallery-toolbar li:last-child { float:right }
  #gallery-title { ?? }
  </code></pre>
  
  <p>I have tried the class "btn-group-jastified" but it didn't work at all.</p>
  
  <p>any ideas?</p>