+ /**
+ Sets appearance of value cells representing an unspecified property
+ value. Default appearance is blank.
+
+ @remarks If you set the unspecified value to have any
+ textual representation, then that will override
+ "InlineHelp" attribute.
+
+ @see wxPGProperty::SetValueToUnspecified(),
+ wxPGProperty::IsValueUnspecified()
+ */
+ void SetUnspecifiedValueAppearance( const wxPGCell& cell );
+