ArcMap Search Window clear button

[Anonymous User]

I have been wondering quite long time about the Search Window clear button (see image below) in ArcMap (10.3).  I think it is a clear button, but it does nothing.  Does it supposed to work as a clear button (deleting text in the input box) or just a symbol?  Interestingly, when I double click right mouse, the X symbol disappears.  There is no problem for the function, but it would be nice if it works as a clear button since some tools have long names.

Best,

Makiko