Difference between Firefox 1.0.3 to 1.0.4

If you want to develop firefox extensions, be careful even minor version up.
Today, I have trouble about this.

Before 1.0.3, we can write,

var searchStr = focusedWindow.__proto__.getSelection.call(focusedWindow);

But after 1.0.4, we must write,

var searchStr = focusedWindow.getSelection().toString();

I hope this can help you.