Click-through overlays ?

[Nitefang]

I'll start by admitting my newbishness, so please forgive me if this is a dumb question and just point me in a direction lol.... I've looked all over the site for a post I read a while back regarding this - but now I cant find it anywhere.

what I'm after is being able to click or mouse over a window thats underneath another (transparent) one, (to either access right clicking features or the mouse-over tool tips for example) I'm sure I read the this is doable - but not finding it now

any help is appreciated