how can i get the blue color WITH a legend?

[amien]

i created this chart. 2 dimensions (week,year) and 1 expression.

When i choose 1 single color, i get the above chart... but when i select 1 single color, i don't get legend with year.

When i select color by dimension i do get an legend. But how do i change the color to get the same results as in the image?

Thanks in advanced