+.SH PORTABILITY
+.PP
+The panel facility was documented in SVr4.2 in
+\fICharacter User Interface Programming (UNIX SVR4.2)\fP.
+.PP
+It is not part of X/Open Curses.
+.PP
+Aside from ncurses, only systems based on SVr4 source code,
+e.g., Solaris provide this library.