Resizing windows : "handle"... what's the deal.....

[Vincent Trouilliez]

Sometimes, when a window is resize-able (a Nautilus window, application
window...), the bottom right corner of the window is "hatched".
It makes it easy for the mouse to grab the corner to resize. Also, I
must say that, from a aesthetics point of view, it looks quite nice. 
Problem : as you can see in the screen capture below that I just made,
only a few windows actually have this nice appendice. Most other windows
don't have it and look a bit dull (IMHO...) as result.

http://www.007.org.uk/~vtrouilliez/temp/Screenshot.png

.... why is that ? Why don't ALL resizeable windows feature a hatched
corner ?? :o(

Vince