search dialog range icon

[Bill <200309 scshop com>]

Select 'Edit > Search' opens the search dialog.

Near the bottom is a radio button:
O Range [Sheet1!$A:$A    ] {icon}

When clicking on the {icon} a small dialog opens with only:
[Sheet1!$A:$A    ] {icon}

I assumed that this would allow me to re-select a range, click the {icon}, and the range would be changed... 
but I can not seem to make that work.

Now I suppose my assumption is wrong.
What is the purpose of that dialog?
How to use it?