Firefox addon shows name but no icon in Customize window

Question

I have recently developed a Firefox addon using the SDK. However, once installed the icon does not show, but only the name of the addon in the Customize window for the addon bar (or the menu in Australis). I haven't seen this behavior in other addons, so I'm guessing it is probably something I did wrong. Maybe I didn't include the right sized icon? My package.json contains the lines:

 ...
 "icon": "data/icons/icon32.png",
 "icon64": "data/icons/icon64.png",
...

The icons display well in the widget and in the addon page. Shouldn't that be enough?

Answer 1

Your code snippet looks correct but it's hard to tell without more context. Here is the full package.json file for an add-on I wrote that works fine for me on Firefox 29+:

{
    "name": "transmission-web-helper", 
    "license": "MPL 2.0", 
    "author": "Jeff Griffiths",
    "version": "0.4", 
    "fullName": "transmission-web-helper", 
    "id": "transmission-web-helper@canuckistani.ca", 
    "description": "a basic add-on", 
    "icon": "data/icon48.png",
    "icon64": "data/icon64.png",
    "preferences": [{
      "name": "transmissionUrl",
      "title": "URL for Transmission RPC",
      "type": "string",
      "value": "http://localhost:9091/transmission/rpc"
    },
    {
        "description": "If selected, torrents will start automatically.",
        "type": "bool",
        "name": "transmissionAutostart",
        "value": true,
        "title": "Auto-start?"
    },
    {
        "description": "If selected, this add-on will print debug .",
        "type": "bool",
        "name": "transmissionDebug",
        "value": false,
        "title": "Debug"
    }
    ]
}

Full source for the add-on is on github