If I group several items together in the Workitem Statistics viewlet (e.g. several status values) and double click on the resulting bar, a dialog pops showing the different parts I grouped together.... allowing me to select one and get the details displayed.
I'm creating a BIRT report chart and want to provide a similar functionality...
I selected the "Hyperlink" option in the Birt report to display the underlying query. This works. But I'm only able to filter for a specific attribute and a single value....  so I need to provide some initial selection dialog for the user to be able to select what specific value he wants to see. 
Anyone having some snippets how to do it (e.g. how the Workitem Statistics is doing it)?

PS: Ideally I wanted to display the set of workitems I'm displaying in the report chart... but pretty sure that this is not possible since the OOTB viewlets are not doing it either.