Secondary Chart only works the first time

I've built a dashboard interface that loads a stacked column chart. This chart displays a column for each manager of a department and each stack is a category of billable hours aggregated for all of the people that report to that manager. All works well.

Subsequently I've added a link to the chart series creation script that saves a manager's name to local variable and then subsequently will generate a second chart that supplies more detail on an employee by employee basis.

So the second chart creates a column for each employee, and the same categories of billable hours, but aggregated for the individual employees.

The problem is that the secondary chart only works the first time I click the primary chart. Subsequent clicks produce an empty chart with the correct employee names across the bottom, but no columns.

Ideas?

OriginalPostID-209666

OriginalPostID-209666