Fix scroll keys in Firefox

web/viewer.html

@@ -265,11 +265,7 @@ limitations under the License.
                     data-l10n-id="page_rotate_ccw"></menuitem>
         </menu>
 
-<!--#if (FIREFOX || MOZCENTRAL) -->
-<!--    <div id="viewerContainer"> -->
-<!--#else -->
         <div id="viewerContainer" tabindex="0">
-<!--#endif -->
           <div id="viewer"></div>
         </div>
 

web/viewer.js

@@ -2015,6 +2015,11 @@ window.addEventListener('keydown', function keydown(evt) {
       return; // ignoring if the 'toolbar' element is focused
     curElement = curElement.parentNode;
   }
+//#if (FIREFOX || MOZCENTRAL)
+//// Workaround for issue in Firefox, that prevents scroll keys from working
+//// when elements with 'tabindex' are focused.
+//PDFView.container.blur();
+//#endif
 
   if (cmd === 0) { // no control key pressed at all.
     switch (evt.keyCode) {