[Seaside] Lightbox-like at inserted position

[itsme213]

I'm not really ready to undertake something like this right now, but just 
want some input on whether the idea makes sense,  is reasonably feasible (or 
even is trivial to do, or already done :-), is not too aesthetically 
horrible, etc.

Lightbox disables an entire existing page and overlays a live modal 
component in the middle. I want to insert that live modal component into the 
right position in the page structure (e.g. where a to-be-inserted element 
will go upon successful completion, or where a collection of elements exists 
that I want to overlay a modal Sorter on), and then disable everything else 
except that one modal component. More or less like a :

    SubComponent >> callWithAllElseDisabled: someComponent

Thanks - Sophie

p.s. what is the basic technique that lightbox uses to disable the existing 
components?