Click noise when in "N"

[Daggerpie]

May be a silly question and they all do this but, when I put it in "N",(at the traffic lights for example), when I let my foot off the brake there is a small "click" noise from under the gear selector, then if I put my foot on the brake again..same click noise..

Is this the norn, I've never really noticed it before but it may have been drowned out by the radio or something??

Cheers