title: How to prevent an angular-bootstrap dropdown from closing (Unbind Event which was bound by a directive)
body: <p>I am using the Angular-Bootstrap Dropdown. I want to prevent it from closing on click until the user closes it intentionally. </p>
  
  <p>Default state is: The Dropdown closes when clicking somewhere in the Document. </p>
  
  <p>I identified the relevant lines of code: (Line 12, dropdown.js) </p>
  
  <pre><code>this.open = function( dropdownScope ) {
     if ( !openScope ) {
       $document.bind('click', closeDropdown); // line to unbind
       $document.bind('keydown', escapeKeyBind);
     }
  }
  </code></pre>
  
  <p>You can find the full code here: <a href="https://github.com/angular-ui/bootstrap/blob/master/src/dropdown/dropdown.js#L12">Link to Github</a></p>
  
  <p>I don't want to change the original sources of angular-bootstrap to keep my project open for updates. </p>
  
  <p>My question: </p>
  
  <p><strong>How can i unbind an event bound by a Directive to the document in an Angular Controller?</strong> </p>