For some users, having the week shown in dropdown calendars is an important thing.
This is what it looks like:
There is an option to show week numbers in the dropdown date picker used by OFBiz. (datetimepicker)
It can be done by adding "showWeek: true," in the datetimepicker calls in framework/widget/templates/htmlFormMacroLibrary.ftl.
Proposed patch for trunk: