Glyphicons not being displayed by Firefox
Firefox isn't displaying certain icons on certain websites like Tumblr and Twitter (hearts, stars arrows and others) which work in other browsers. I've found out these are apparently called Glyphicons from glyphicons.com ? Instead of the icons, Firefox displays rectangles with a letter/number code in them.
Todas as respostas (2)
Those symbols mean that the computer does not know how to display the character. You need to install something for this.
The missing icons are supplied by a font that is downloaded from the server (@font-face) as you can probably see by little boxes that show the hex code of the characters.
Make sure that you allow pages to choose their own fonts.
- Tools > Options > Content : Fonts & Colors > Advanced: [X] "Allow pages to choose their own fonts, instead of my selections above"
You can check the gfx.downloadable_fonts.enabled pref on the about:config page and make sure that it is set to true (if necessary double-click the line to toggle its value).