FontAwesome Icon on Button not shown

I found this FontAwesome torubleshooting page. Maybe you could check if some of these apply to your situtation?
https://github.com/FortAwesome/Font-Awesome/wiki/Troubleshooting#some-icons-dont-show-up

Hi Johannes,

thanks for the answer and sorry for the late reply.

Johannes Häyry: I found this FontAwesome torubleshooting page. Maybe you could check if some of these apply to your situtation?
https://github.com/FortAwesome/Font-Awesome/wiki/Troubleshooting#some-icons-dont-show-up

I did check the points, here are my comments:

1. You don't have an old version of Font Awesome installed on your system (it may have priority) and you didn't restart your machine;
• The version Vaadin uses is 4.4.0. The icon that is not displayed, was introduced in 4.2.0 (https://github.com/FortAwesome/Font-Awesome/issues/171).
2. If you are serving Font Awesome from your own server: both font-awesome.css file and /fonts folders are up to date;
• This is something that Vaadin handles. Since other Icons work, I assume this is true. To be safe I tried recompiling the Widgetset, but nothing changed.
3. If you are serving Font Awesome from a CDN: Font Awesome's css link is up to date (ref: #1490);
• Same answer as 3. Vaadin handles this. I tried finding the link to the fontawesome files. I found links in the styles.css theme:

@font-face {
font-family: FontAwesome;
font-weight: normal;
font-style: normal;
src: url(../valo/util/bourbon/css3/../../../../base/fonts/fontawesome-webfont.eot);
src: url(../valo/util/bourbon/css3/../../../../base/fonts/fontawesome-webfont.eot?#iefix) format("embedded-opentype"), url(../valo/util/bourbon/css3/../../../../base/fonts/fontawesome-webfont.woff) format("woff"), url(../valo/util/bourbon/css3/../../../../base/fonts/fontawesome-webfont.ttf) format("truetype"), url(../valo/util/bourbon/css3/../../../../base/fonts/fontawesome-webfont.svg#FontAwesome) format("svg");
}

• They all work

4. You are using valid HTML5 templates (check the W3C Markup Validator);
• I checked it with the W3C Markup Validator. Asides a few warnings that seem harmless, it looks ok.
5. You are not using plugins/extensions which are loading older/modified versions of Font Awesome (ref: #1546);
• No we do not use any.
6. You are not using any JavaScript or CSS libraries that reset/change/override css properties on the icon tags;
• Nope.
7. Your browser's development console shows that you are loading the proper font files;
• Other FontAwesome Icons are there, so this is not the issue.
8. Your browser's extensions are not blocking webfonts (noscript, adblockplus, etc.);
• No none.
9. Your operating system is not blocking webfonts (Microsoft Group Policy)
• Also no

I also checked the warnings in the WebDeveloper Console but did not see anything supicous.

Any other Ideas, why this issue occurs?

I found a fix by using the FontAwesomeLabel Add On:

https://vaadin.com/directory/#!addon/fontawesomelabel

I'm glad that helped. I didn't know about that add-on. I'll check it out.