The node highlight should show the highlighted node's metrics overlaid on top of the node. Firebug uses different colors to show the different boxes. It might be nice to show the actual numbers as well, if we can keep them from obscuring things too much.
<rdar://problem/5732822>
Created attachment 19911 [details] Show content/padding/border/margin boxes for blocks Here's a patch that changes our node highlight pretty drastically (screenshot coming). We now outline the content/padding/border/margin boxes for blocks. We don't yet show padding/border/margins for inlines.
Created attachment 19912 [details] Screenshot of new highlight Here's what the highlight implemented by attachment 19911 [details] looks like. I think we'll want to tweak this a bit more, at least to make the different boxes more distinguishable. Firebug uses some high-contrast colors that get the job done, but are a bit ugly.
Created attachment 19913 [details] Firebug's highlight Here's Firebug's highlight, for reference
Created attachment 19914 [details] Xyle scope's highlight
Comment on attachment 19911 [details] Show content/padding/border/margin boxes for blocks Committed in r31189
Reopening as we may want to show numeric metrics in the node highlight as well.
We've had numeric metrics displayed as a tooltip for a while. Bug 37768 patch slightly changed the appearance of the tooltip but it still contains the element renderer's dimensions. Please reopen if you envision something specific that should be implemented.