deleting specific legend keys in mixed line-scatter chart not corr
 

In Excel 2007, I have a mixed line-scatter chart with 4 line (labeld 'A' to
'D') and 4 scatter series (labeled 'A mean' to 'D mean') which represent
average values of respective line series. A to C and respective mean series
are linked to 1st Y-axis, D and D mean to 2nd Y-axis.
I only want to show keys for line series (A to D). When I delete the
non-wanted keys (all mean labels) Excel shows the correct legend. When I save
and reopen file, legend is messed-up; only serie keys A to C are shown, not
D, insteda one of the mean keys is shown. Why is that ?