Problem with double-mouse-1.

[luca . spinacci]

I'd like to double click on a function simbol to get to the corresponding
buffer.
I wrote in my _emacs file:
(global-set-key [double-mouse-1] 'goto-symbol)

but it behaves like function mouse-set-point...

Instead
(global-set-key [C-down-mouse-1] 'goto-symbol)
works as expected.

Any idea?
Thanks in advance.
Luca.