css driving editing

I have a question about CSS for defining how and where a document may be 
edited. This seemed to be working its way through the standards (see: 
(http://www.w3.org/TR/1999/WD-css3-userint-19990916#user-modify)) and 
then seemed to go away ... However, Mozilla did add this CSS in "-moz-" 
properties though their semantics weren't implemented in its base 
engine. They are being implemented as part of an inline editor project 
called Mozile - see http://mozile.mozdev.org.

My questions are two:
- does anyone know why "user-modify" was dropped from the level 3 
standards?
- is there some other work going on that addresses using CSS to drive 
how and where a document may be edited?

thanks for any info.