lower bounds check
diff --git a/NatTable/src/org/eclipse/nebula/widgets/nattable/core/layer/axis/AxisInvariants.xtend b/NatTable/src/org/eclipse/nebula/widgets/nattable/core/layer/axis/AxisInvariants.xtend
index 849d4d6..168d2f9 100644
--- a/NatTable/src/org/eclipse/nebula/widgets/nattable/core/layer/axis/AxisInvariants.xtend
+++ b/NatTable/src/org/eclipse/nebula/widgets/nattable/core/layer/axis/AxisInvariants.xtend
@@ -14,11 +14,11 @@
 	}
 	
 	def static boolean containsPixelLocation(Axis axis, int pixelLocation) {
-		pixelLocation < axis.getStartPixelOfSegmentPosition(axis.segmentCount)
+		pixelLocation >= 0 && pixelLocation < axis.getStartPixelOfSegmentPosition(axis.segmentCount)
 	}
 	
 	def static boolean containsSegmentPosition(Axis axis, int segmentPosition) {
-		segmentPosition < axis.segmentCount
+		segmentPosition >= 0 && segmentPosition < axis.segmentCount
 	}
 	
 }
\ No newline at end of file