In DateTickUnit, the 'week' tick is not implemented.
Thanks for added it in the next versions.
Logged In: YES
We implement the units using the date arithmetic provided by the java.util.Calendar class. This offers WEEK_OF_MONTH and WEEK_OF_YEAR fields, but I decided to omit these because those fields have unusual characteristics around the end of month and year boundaries. Just use DAY with a count of 7.