Graph view does not handle combination of multiple columns and grouping

[Xavier (Open ERP)]

This is not natively supported by our graphing library, according to al "it's low priority and nobody uses it anyway".

It might be possible to hack it in in a manner similar to Excel or Numbers (which also do not support clustered stacked bar charts): http://peltiertech.com/WordPress/clustered-stacked-column-bar-charts/

But according to dhtmlx folks, this would require "heavy customization" of the grid code: http://forum.dhtmlx.com/viewtopic.php?f=8&t=20605

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original report:

fwd odo: Have a look at the invoice.report graph view, visible in
Accounting>Reporting>Statistics Reports>Invoice Analysis.

If you redefine it as:

<graph string="Invoices Analysis" type="bar">
                <field name="product_id"/>
                <field name="price_total" operator="+"/>
                <field name="residual" operator="+"/>
                <field name="partner_id" group="True"/>
</graph>

You're supposed to see 2 bars per product (price and redsidual), both
being vertically split by partner_id contribution.
The last part (group=True) seems to work sometimes, e.g. if you only
have one bar in the graph.