+ <STRONG>o</STRONG> If <STRONG>delwin</STRONG> is asked to delete a parent window, it can only succeed
+ if the curses library keeps a list of the subwindows. SVr4 curses
+ kept a count of the number of subwindows rather than a list. It
+ simply returned <STRONG>ERR</STRONG> when asked to delete a subwindow. Solaris
+ X/Open curses does not even make that check, and will delete a
+ parent window which still has subwindows.
+
+ <STRONG>o</STRONG> Since release 4.0 (1996), <EM>ncurses</EM> maintains a list of windows for
+ each screen, to ensure that a window has no subwindows before
+ allowing deletion.
+
+ <STRONG>o</STRONG> NetBSD copied this feature of <EM>ncurses</EM> in 2003.
+ PDCurses follows the scheme used in Solaris X/Open curses.
+
+
+</PRE><H2><a name="h2-BUGS">BUGS</a></H2><PRE>
+ The subwindow functions <STRONG>subwin</STRONG>, <STRONG>derwin</STRONG>, <STRONG>mvderwin</STRONG>, <STRONG>wsyncup</STRONG>, <STRONG>wsyncdown</STRONG>,
+ <STRONG>wcursyncup</STRONG>, and <STRONG>syncok</STRONG> are flaky, incompletely implemented, and not
+ well tested.
+
+ System V's <EM>curses</EM> documentation is unclear about what <STRONG>wsyncup</STRONG> and
+ <STRONG>wsyncdown</STRONG> actually do. It seems to imply that they are supposed to
+ touch only those lines that are affected by changes to a window's
+ ancestors. The language here, and behavior of <EM>ncurses</EM>, is patterned on
+ the X/Open Curses standard; this approach may result in slower updates.