On modern websites, icons (such as the search icon) are generally displayed using a custom font, instead of an image, which was the practice in the past. If you have set Firefox to prevent websites from using their own custom font, then Firefox will not be able to display the icons.

To fix this, do the following:

1. Open the Firefox settings or type about:preferences in the Firefox address bar
2. Select the General tab
3. Find the Fonts & Colors section
4. Select the Advanced... button in that section
5. Ensure that the Allow pages to choose their own fonts, instead of your selections above option is checked

NOTE: You may need to restart Firefox for the changes to take effect.

Note that this isn't 'fl' (FL), but is F1xx denoting the F000-FFFF Unicode block.

Special icons are usually supplied by a special icon font that is downloaded from the server (@font-face) You may see little boxes with the hex code of the character if you do not have a font installed that covers this Unicode range.

You can check gfx.downloadable_fonts.enabled on the about:config page and make sure it is set to true (if necessary double-click the line to toggle its value to true).

There are also extensions that can block downloadable fonts, so if you have any content blocking extensions then make sure they do not block these font files. You can also check the Web Console for font related messages.

• "3-bar" menu button or Tools -> Web Developer
• https://developer.mozilla.org/en/Tools/Web_Console