Timeline Slicer - 2017 with 53 Weeks

I think it's because the American method of week numbering differs from the ISO / European week numbering method. We over here in Europe, normaly use Monday as the start of the week and in case January 1 is on Monday, Tuesday, Wednesday or Thursday, that week is the 1st week of the next year. In case January 1 falls on Friday, Saturday or Sunday, the weeknumber is increased +1 with the previous weeknumber of last year. This is different from the "USA"-method, where the first week of the year depends on what day January 1 falls: in case it's a Sunday, PowerBI calculates week 1, otherwise it calculates a next weeknumber of the previous year for that week.

Outlook uses two settings to solve this:

- First day of week (in USA: Sunday, but in Europe, according to ISO weeknumbers: Monday)

- First week of year (in USA: Starts on January 1, but in Europe, according to ISO weeknumbers: First 4-day week).

In my opinion, the Timline slicer should be extended with the First Week Of Year setting to solve this issue of incorrect week numbers.

When you set the week start in the Timeline slicer to Mondays, the weeknumber looks correct for European weeknumbers in 2017 and 2018, but in that setting 2018 has 53 weeks instead of 52 because January 1 2019 starts on a Tuesday.

So I guess the Timeline slicer needs to be extended with the First week of year setting, like in Outlook.