- * This is provided for use by Structure Viewers and the Overview Window to
- * get the feature colour of the rendered sequence.
+ * If no transparency applies, then the graphics argument may be null, and the
+ * returned colour is the one that would be drawn for the feature.
+ * <p>
+ * Returns null if there is no visible feature at the position.
+ * <p>
+ * This is provided to support rendering of feature colours other than on the
+ * sequence alignment, including by structure viewers and the overview window.
+ * Note this method takes no account of whether the sequence or column is
+ * hidden.