The default dialog button will be marked by shading to indicate it is the default and you can use the "Enter" key, which I have set to the mouse middle-click button as a Global default and specifically for Firefox as well..

I have that control panel setting for my IntelliMouse mice, and strangely the cursor was placed on the default button. I just build up habits of when to hit "Enter" on the keyboard, or the mouse, or click on the dialog box first so the "Enter" will work that I don't pay much attention to it.

I'm afraid I don't understand how your reply relates to my problem. I'll type the words I don't understand in your answer: "default dialog button" (where do you find this?) "mouse middle-click button" (I have a wheel) "Global default" I don't know what that is, so, apparently, it doesn't apply to me. "IntelliMouse" I don't have this either, just an old, dumb "Dell mouse"  ;-) "dialog box" is that what I'm hoping the cursor will be moved to? If so, how do I get it to move there on it's own? What's the purpose of "Snap to" if I have to move the cursor there myself?