Help with Subscribed Treads in User Control Panel

Hi,

I'm beginner and I don't know where to post this message (sorry if it is in the wrong place).


In the User Control panel , I want to display by default the subscribed thread of the last 30 days.

I could not find where to change the default which is "last day "

I tried the
- user account Default view age = -1 and
- the forum set to 30 but it did not work

does it require some extra coding ?

Can someone help me
Thanks in advance

Matt
(from Switzerland)