diff --git a/man/rgbgfx.1 b/man/rgbgfx.1
index ffc7e4c6..86eb37c6 100644
--- a/man/rgbgfx.1
+++ b/man/rgbgfx.1
@@ -13,6 +13,7 @@
 .Op Fl CmhOuVwXYZ
 .Op Fl v Op Fl v No ...
 .Op Fl a Ar attrmap | Fl A
+.Op Fl B Ar color
 .Op Fl b Ar base_ids
 .Op Fl c Ar pal_spec
 .Op Fl \-color Ar when