Leverage summary table as data source of charts

[mjason24]

Describe the problem to be solved

I don't know why we can't use summary table as data source of a line chart.
I have a detailed expense table with individual transactions, I'd like to produce a monthly cumulative expense line chart.

Date	Expense Type	Name	Amount

Summary Table:

Date	Amount	CumulativeAmount

I'd like to use Summary table to generate line chart, but I can't.
The only way I can do is still choose data source from expense table grouping by Date. Then unexpectedly I can choose 'CumulativeAmount' from series. This behavior looks weird to me.

The other issue related to above behavior is -
I generated two different summary tables from same data source with different group columns. Seems I can see all the new columns added to different summary tables. When I use the same column name in different summary table, if you show all of them in Series, it's hard for me to tell which one is from which summary table.

Describe the solution you would like

I will suggest to allow generating chart from a summary table.