Extra pixel around square vector filler for polygon

[Jani Averbach]

Hello, 

I have a map which uses a checkerboard pattern as polygon filler.
The filler is a square which consists of four checks (two white, two black),
and when mapserver renders a polygon using this pattern, it puts an extra
1 pixel wide border for east and north side of square.

I will paste example map file and symbol definition at the end of this email,
so if you have any idea if this is a feature or bug, and how to get rid of this 
or what is more appropriate way to draw checkerboard I would be grateful.

BR, Jani

----------------------8<------------------------8<-----------------
SYMBOL
  NAME "checkerboard"
  TYPE VECTOR
  POINTS
    0 0
    0 1
    1 1
    1 0
    0 0
    -99 -99
    1 1
    1 2
    2 2
    2 1
    1 1    
  END
  FILLED TRUE
END

----------------------8<------------------------8<-----------------
MAP
	SIZE 40 80
	SYMBOLSET "symbols/symbols.sym"
	EXTENT 0 0 40 80
	UNITS METERS
	IMAGETYPE PNG
	IMAGECOLOR 0 0 0 
	RESOLUTION 96
	
	LAYER
		TYPE POLYGON
		STATUS DEFAULT
		FEATURE
			POINTS
				5 44
				35 44
				35 80
				5 80
				5 44
			END
		END
		CLASS
			STYLE
				SYMBOL  "checkerboard"
				SIZE 16
				COLOR 255 255 255
			END
		END
	END

	LAYER
		TYPE POLYGON
		STATUS DEFAULT
		FEATURE
			POINTS
				5 0
				35 0
				35 36
				5 36
				5 0
			END
		END
		CLASS
			STYLE
				SYMBOL  "checkerboard"
				SIZE 4
				COLOR 255 255 255
			END
		END
	END
END

----------------------8<------------------------8<-----------------