I need to call out only certain points on my charts and so I have been using
the Arrow and Text Box tool from the Drawing toolbar. If I open the file
later, I sometimes find some of the lines and boxes have shifted. But it
doesn't occur on all graphs.

I have done a search already but it doesn't quite do what I'm looking for.
I need a means to enter my own comment/label and point to the datapoint. XY
Chart Label makes a label but doesn't create an arrow to correspond. With
the amount of the datapoints I have, I would have to create an arrow which
could easily shift as it is happening now.

What I need is something like the Comment tool in the spreadsheets
themselves but permanently visible, even when printing. Any suggestions on
how to accomplish this?