Takayuki Miyoshi on "[Plugin: Contact Form 7] Repeated Submissions from Multiple Clicking of Submit Button"

I guess multiple clickings happen because people don't detect the spinning arrow icon shown right of the submit button during submission. How about making it more appealing by changing its style with CSS like this?

.wpcf7 img.ajax-loader {
	background-color: white;
}

See also: Styling Contact Form