Good afternoon. I've encountered an infuriating problem in Excel charts, and
I haven't found a solution in Excel or on Google. Has anyone else seen this?
I'm using Excel 2K3, Windows XP, fully patched up. It's happend to other
users on other computers, too.

On some charts, the plot area for a chart can shrink, or occasionally grow,
on it's own. I'll just click on the chart and the plot will shrink slightly,
and possibly move slightly too. This happens each time I click on it, and
sometimes when I open the workbook, or work on other charts. There's
typically some visual corruption, too, the plot area box will remain visible,
slightly. Once a chart gets "infected" it will not stop, and I have to
either periodically stretch out the area again, or delete it and recreate it.
This can happen on pie charts and line charts, that I've noticed. It seems
to happen in larger Excel files, 5+ MB, and mostly only when charts' areas
overlap, but that's not all there is to it: sometimes a lone chart will be
affected, and sometimes overlapping charts are fine.
I'm quite sure I'm not accidentally dragging the plot area, or a resize
handle. It'll happen when I'm moving the chart, or clicking on the labels.
It's not from deleting or resizing rows or columns, all of my charts are
move-but-don't-resize and I'm not working with rows or cells at all on these
worksheets.

This is especially maddening when I'm linking Excel charts into PowerPoint.
I may paste in four equal-sized pie charts, and after some twiddling I come
back and one pie has shrunk to a pinpoint. On other slides I have line
charts neatly lined up with a PPT rectangle object to highlight a section,
and every time I open the file I need to adjust the chart's plot area again.
I don't remember seeing this before I started working with PowerPoint, so I
suppose there could be something about the OLE linking process that causes
Excel to handle charts differently, but if so it only affects a few.

This seems like a cumulative rounding error, maybe. Has anyone seen this?
Any ideas how to stop it? I'll give you my first born son!