Debugging Silverlight with Visual Studio and Firefox

Here’s how to ensure the VS debugger attaches to the Silverlight app for debugging:

1- In Firefox address bar type about:config
2- Read the warning, choose your preference to always remind you or not and accept
3- In the search bar of the config options now type: npctrl
4- You should then see the entry: dom.ipc.plugins.enabled.npctrl.dll
5- Change the value from true to false (simply double-clicking will change this for you)
6- Restart Firefox