(with screenshots if possible)
Do you have a time machine ?
11g has been released in 2010, so not a single chance to still have a 10g around ...
In 11g it's an attribute in the XML of the analysis, isn't the same in 10g? If there is a way to decide what is bar and what is line (or even both lines or bars) it's there inside.
The company is migrating to 12C next month
If the feature is available in 12C then I can wait to make the improvements in the dashboard then!
I am not involved in the setup of the database and behind the scenes, I'm more focused on creating reports in Answers.