+ /**
+ Sets whether the sash should be invisible, even when the window is
+ split.
+
+ When the sash is invisible, it doesn't appear on the screen at all and,
+ in particular, doesn't allow the user to resize the windows.
+
+ @remarks Only sets the internal variable; does not update the display.
+
+ @param invisible
+ If @true, the sash is always invisible, else it is shown when the
+ window is split.
+
+ @see IsSashInvisible()
+
+ @since 2.9.4
+ */
+ void SetSashInvisible(bool invisible=true);
+