Answer

1. Drag [Region] to the Columns shelf
2. Drag [Sales] to the Rows shelf
3. Drag [Profit] over the axis for Sales and drop the field
4. Move [Measure Names] from the Columns shelf to Colour on the Marks card
5. Create a calculated field with a name like "All or each segment colour" with a calculation similar to the following:
   
   IF { FIXED : COUNTD([Segment])} = {EXCLUDE [Segment] : COUNTD([Segment])}
THEN "All"
ELSE [Segment]
END

   Note: The FIXED expression will always return the total unique count of segments no matter how the view is filtered. The EXCLUDE expression will return the unique count of segments in the view based on how the view is filtered. It is necessary to exclude [Segment] otherwise each mark in the view will return 1 (since each bar segment only has one value of [Segment])

6. Shift-drag [All or each segment colour] to Colour.

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