Allow old graphs to be refreshed/updated to the latest renderings
I have graphs from over 16 years ago that i still use (long-term data collation). The graphs do not update to new graphics (which are a S**t-tonne better). Having an option to update the graphs without losing all the series formatting and data processing would be great! I just did it the long way round for one graph but don't fancy doing it for the other 7. (this may not be an issue with all graph types but for area graphs it really is).