- attributes, first removing those which may have come from the cur-
- rent background, and then adding attributes from the new back-
- ground.
+ attributes, first removing those which may have come from the
+ current background, and then adding attributes from the new
+ background.
+
+ If the background's character value is zero, a space is assumed.
+
+ If the terminal does not support color, or if color has not been
+ started with <B>start_color</B>, the new background character's color
+ attribute will be ignored.