Why does Visual Web Developer 2008/2010 no longer debug silverlight apps in Firefox?

Question

Suddenly today Visual Web Developer does not allow me to debug Silverlight applications.

This happens in 2008 and 2010 versions.

It gives no error message, just ignores all break points.

It can still debug ASP.NET applications.

Is anyone else experiencing this?

Added:

Interesting: debugging works in Internet Explorer but not in Firefox. Also on a new installation on a second computer it debugs in both IE and FF. Just noticed that that FF browser is still version 3.6.3.

I cleared everything in Firefox (3.6.4) but it still doesn't debug in that browser (on two computers):

While uninstalling the Silverlight plugin I saw this:

Answer 1

Mine seems to work fine in both VS2008 and 2010...

Answer 2

Check this link:

http://forums.silverlight.net/forums/t/188434.aspx

The solution seems to be:

Regarding the debugging: I think it would be possible to write a VS plugin or similar to attach to the plugin-container.exe process automatically, however there's a simpler solution. You can disable the new isolation feature in Firefox:

Type "about:config" into FF's address bar Accept the warning (if applicable) Search for the entry "dom.ipc.plugins.enabled.npctrl.dll" Change its value from "true" to "false" (double-click) Restart the browser