Slicer conditional formatting value border color

I didn't find any solution how to do the formatting, if someone has an idea, feel free to answer.

I came around with this solution, that works for me:

I created another table using

Extension Check = DISTINCT(SELECTCOLUMNS(Scan,"Extension",[SourceExtension]))

So I just have a distinct list of all my extensions. Then I use the same formular as above to create a new column:

Extension Check = 
VAR _SEL =
SELECTCOLUMNS('Valid Extension',"Title",[Title])
RETURN
IF('Extension Check'[Extension] IN _SEL, "Supported", "Unsupported")

But this time I put in "Supported" and "Unsupported". This gives me a list with all distinct values and a column if it's supported or not. Using the relationship between the "Scan" and "Extension Check" table using 1-* on the column extension, I can get use the slicer with a second level:

This also helps me to easily select all unsupported or supported extension and solves my problem!

Best regard

Marvin