layers and zindex in Safari

[Lars Knoll]

Hi,

I found the following comment in safaris render_layer code:

    // Find out if we have any elements with negative z-indices in this 
stacking context.
    // If so, then we need to split our layer in two (a background layer and a 
foreground
    // layer).  We then put the background layer before the negative z-index 
objects, and
    // leave the foreground layer in the position previously occupied by the 
unsplit original.

The code which does this doesn't seem to make sense to me. Negative and 
positive z-indices seem to be treated differently concerning the painting of 
backgrounds even though the CSS specs treats them equally (the way you 
currently trat positive z-indices).

Could you tell me the reason why you treat these differently?

Thanks,
Lars