The \'click sound\' in question is actually a system wide preference, so I only want it to be disabled when my application has focus and then re-enable when the application
I've noticed that if you use WebBrowser.Document.Write rather than WebBrowser.DocumentText then the click sound doesn't happen.
So instead of this:
webBrowser1.DocumentText = "Hello, world!";
try this:
webBrowser1.Document.OpenNew(true); webBrowser1.Document.Write("Hello, world!");