Hello - It is not recommended to show a long list (Like all products for a Product Line) in the Tooltip. This need to be done in a separate worksheet and add it to the dashboard. Multiple value for a dimensional field in the tool tip can't be added, Tableau will try to use ATTR function and this will return a * if you have many value in that variable.
Create a Dashboard action to do this. This might be configured on Hovering or on Select, whichever way suits your data and requirement.
Tooltip.twbx 1.2 MB