In many views of OpenERP you can group records, for example by product, date, salesperson etc.

My problem is, the formed groups are often not sorted correctly, eg. the dates (or months) are in wrong order, and sorting by numerical groups results in the contents of the groups getting sorted.

Sorting by numerical columns would allow finding things like top customers, top products etc. very easily. Also the weird date sorting makes for very weird time-series graphs, because the columns will be in wrong order.

My question is, what do I have to do to control sorting of result groups?