explain expected range of getStartPixelOfSegmentPosition
diff --git a/NatTable/src/org/eclipse/nebula/widgets/nattable/core/layer/axis/Axis.xtend b/NatTable/src/org/eclipse/nebula/widgets/nattable/core/layer/axis/Axis.xtend
index 827f8c7..1981b93 100644
--- a/NatTable/src/org/eclipse/nebula/widgets/nattable/core/layer/axis/Axis.xtend
+++ b/NatTable/src/org/eclipse/nebula/widgets/nattable/core/layer/axis/Axis.xtend
@@ -13,6 +13,11 @@
def int getSegmentCount()
/**
+ * Gets the start pixel location of the segment at the given position. This function must be defined for all valid segment position
+ * values and <em>also</em> for segment position = segment count. Technically the segment count is not a valid segment position because
+ * segment positions are 0-indexed and range from 0 to segment count - 1. However, the 'start' pixel location of the segment position after
+ * the last segment is used to calculate the pixel size of the last segment, and also the overall pixel size of the axis.
+ *
* @param segmentPosition
* @return The start pixel location of the given segment position.
*/
