on_change's processed too late
There are some cases where the on_changes are processed too late.
For example, when filling a invoice line by setting the unit price (without loosing focus) and click on "OK". In this case the amount is not updated because the initial on_change which is triggered by the focus out is not yet finished (display is not yet called) when the form call set_value on the view. So the previous value still on the widget is set back.