Click on it to find out. It lets you treat a thread like a treeview node.

>OK. Thats a great idea. Where can I read about that? BTW, what is the square box with a negative?
>
>Chuck
>
>> I am not sure about the prize. But it helps other people reading the thread to
>>know which reply is the soluton to the question posted. I certainly won't miss
>>those marked as the solution and sometimes you may skip those unmarked for saving time. This applies to my tendency of reading the thread messages.