A file containing one worksheet with two charts is at the following
location

www.rotordynamics.org/public/book2.xlsx

For me, the top chart in this file does not show the highlighter, the
bottom chart does.

There aren't a whole lot of points or series in these charts, and the
symbol sizes are the same.

I just re-ran the macro that created that sheet and those charts, and
the charts on the newly created sheet do show the highlighter on both
charts.

I guess Excel 2007 has its own ideas about when to show the
highlighter, and when not to.

Brian