The publication-specific usecase-bxeng.xmap creates a pipeline to show the BXE by calling lenya/xslt/bxeng/index-xhtml.xsl which (among others) defines the <head> section. Inside the <head> section, a css-link is generated by <xsl:attribute name="href"><xsl:value-of select="$context"/>/bxeng/css/editor.css</xsl:attribute> which points to a global editor.css. usecase-bxeng.xmap provides a variable $publicationid which is not used in xhtml-index.xsl. By evaluating this variable, index-xhtml.xsl could point the CSS-link to a publication specific style sheet, like: <xsl:attribute name="href"><xsl:value-of select="$context"/>/<xsl:value-of select="$publicationid"/>/bxeng/css/editor.css</xsl:attribute> or link to a global and a publication-specific CSS. Advantages: Publications that make use of CSS2 to define placement and design of their pages are likely to conflict with the editor.css by z-indexing and/or positioning. A publications-specific editor.css would be a natural way to solve those conflics.
this should be solved with the fallback:// protocol. johannes, feel like sending a patch?