Use readonly attribute instead of disabled. Disabled text fields are not selectable on FireFox.

#225

cms/templates/asset_index.html

@@ -28,7 +28,7 @@
         {{uploadDate}}
       </td>
       <td class="embed-col">
-        <input type="text" class="embeddable-xml-input" value='{{url}}' disabled>
+        <input type="text" class="embeddable-xml-input" value='{{url}}' readonly>
       </td>
     </tr>
   </script>
@@ -84,7 +84,7 @@
                 ${asset['uploadDate']}
               </td>
               <td class="embed-col">
-                <input type="text" class="embeddable-xml-input" value="${asset['url']}" disabled>
+                <input type="text" class="embeddable-xml-input" value="${asset['url']}" readonly>
               </td>
             </tr>
           % endfor
@@ -115,7 +115,7 @@
 			</div>
       <div class="embeddable">
         <label>URL:</label>
-        <input type="text" class="embeddable-xml-input" value='' disabled>
+        <input type="text" class="embeddable-xml-input" value='' readonly>
       </div>
 			<form class="file-chooser" action="${upload_asset_callback_url}"
                                 method="post" enctype="multipart/form-data">