title: Officejs Changing Footer font style makes it disappear
body: <p>In my code I am trying to change font style of footer. When I run the following code my Footer disappears.</p>
  
  <pre><code>function applyFontPreference(optionNo){
      Word.run(function (context) {
          const sections = context.document.sections;
          sections.load('body/font');
          return context.sync().then(function(){
              var footer = sections.items[0].getFooter("Primary")
              footer.font.name = "Arial";
          });
      }).catch(function (error) {
          console.log("Error: " + error);
          if (error instanceof OfficeExtension.Error) {
              console.log("Debug info: " + JSON.stringify(error.debugInfo));
          };
      });
  }
  </code></pre>