Hi
This is more of a 'what to check if you see this' hint than a bug request, as it's symptoms are down to incorrect incoming configuration data.
On a Multi Line graph (MSLine.swf), if you happen to mistakenly set a dataset colour to 'null' (e.g. in JSP extracting colour values from an array in a forEach loop, using the status variable's 'count' field ... <duh/> ) the line plot comes out black, but oddly, the circle in the legend's icon for the plot comes out light grey (though the cross bar is black). This confused me for some time...
Cheers!
