Dates table outside slicer selection

Anonymous 

If I understood your question correctly, you need to have an additional dates table to have the desired result. Create a measure to filter the Extended table Viz as follows:

ExtendedDateFiter = 
VAR __DATEMIN = MIN('Dates'[Date])
VAR __DATEMAX = MAX('Dates'[Date])
VAR __DATEEXT = SELECTEDVALUE('Dates Extended'[Date])
VAR __RESULT = 
INT(
    __DATEEXT >= __DATEMIN - 7 &&
    __DATEEXT <= __DATEMAX + 7
)
RETURN
    __RESULT

File is attached.