Change Who's Online default for users per page

[Benjidog]

This query relates to vb4 version 4.2.2. The default setting for the number of online users per page on the Who's Online screen is 20 and I want to change this to 100. There is nothing to change this in the "Who's Online" section of the Settings.

I have looked at the page with Firebug and can't find anything particularly helpful there - see below.

<div class="blockrow">
<label for="pp">Per Page:</label>
<input id="pp" class="numeric textbox" type="text" tabindex="1" size="5" value="20" name="pp">
</div>

The URL when looking at this screen shows online/php but I can find nothing hard-coded in there so am at a loss to locate the relevant setting.

Not a big deal but if anyone knows how to change this I would appreciate your advice