Can you add cancel button when it's possible?

[Xan]

Hi,

Recently I thought that, in some preferences dialog, it's useful to have "ok" 
and "cancel" button (or maybe "ok", "apply" and "cancel" buttons) rather than 
only "ok" button.

I will try to explain it better I know.  For example, imagine this situation: 
a (novice) user of xfce4. This user has "variation" wm theme and he/she wants 
to change it. He/she go to wm theme dialog and try what themes like to 
him/her. He/she don't like any new theme more than the old theme. So he/she 
wants their original theme but he/she doesn't know what theme is it. So 
he/she has to try all themes until he/she finds it. 

With "cancel" button it's a second.

I don't know if I explain it correctly.

The same happens in almost all preferences dialogs.

Thanks,
Xan.