How are kcontrol module window sizes determined when launched from kcmshell?

For example, 'kcmshell audiocd' opens to a window size of 765,778 and 'kcmshell media' opens to a window size of 765,512.

I get the feeling the width of 765 is hard-coded somewhere but I can't find anything. I'd like to know how the width number is fixed, but at the moment I am more interested in how the height is determined for each window.

Thanks.

Darrell