The format for the domain autocompletion string will be like www.*.com, www.*.com.us. Domain autocompletion only happens when you type a single-word identifier with the corresponding key combinations. It will replace the asterisk symbol with the identifier you've typed. For example, if you type "domain" in the address bar, after domain autocompletion, it will be www.domain.com or www.domain.com.us.
Enter: the string that'll be used for autocompletion when you press ENTER in the address bar.
Ctrl+Enter: the string that'll be used for autocompletion when you press Ctrl+ENTER in the address bar.
Shift+Enter: the string that'll be used for autocompletion when you press Shift+ENTER in the address bar.
Ctrl+Shift+Enter: the string that'll be used for autocompletion when you press Ctrl+Shift+ENTER in the address bar.
The last three options will be in effect only if you have enabled the option "Use ctrl/shift key for domain autocompletion" in the same page.
This option will set the engine used for direct keyword search in the address box. If what you type in the address box is a phrase containing spaces and it can't be interpreted as a valid web address, $ProductName will pass the string to the selected search engine. Please notice that this option will NOT set the default search engine on the quick-search bar.