Normally default values are not exported to ODF files in order to reduce file
size and optimize performance.
It turns out that default values are exported nevertheless in case they have
been set explicitly via the user interface or API before. This is wrong.
To reproduce
-create a default chart from any simple data and save it.
-Look into the according content.xml stream -> you will for example find no string
fo:font-style="normal"
because this is the default style for fonts. All fine so far.
-Now change the font style of any chart element to 'italic' via dialog
-click ok in the dialog
-change it back to 'regular'
-again accept the changes with clicking ok in the dialog.
-Save the file and look at the according content.xml stream again.
->You will find fo:font-style="normal" - but it should not be exported for
performance and file size reasons.