shrinked Y-axes
 

I have an Excel 2007 sheet with several charts of which one with 2 Y-axes.
One time, when I opened the sheet, the latter chart is invisible until I
make a print preview and then it shows up. When it's finally showed, the
Y-axes are shrinked but still in the correct scale. Also the series located
to the 2nd Y-axis is not showed. When I finally select this series (by layout
tab), the series could not be allocated to the 2nd axes.
What's happening ?.