Add missing UI objects: uicontextmenu, uitoolbar, uipushtool and uitoggletool. * graphics.h.in (uicontextmenu, uitoolbar, uipushtool, uitoggletool): New graphic object classes. (uicontrol::properties::cdata): Allow "single" and "uint8" data. * graphics.cc (uitoolbar): New class implementation. * gl-render.cc (opengl_renderer::draw): Skip new object types. * plot/private/__uiobject_split_args__.m: Don't use varargin. Add parent_type and use_gcf arguments. Check that number of arguments is a multiple of 2. * plot/uicontrol.m: Adapt call to __uiobject_split_args__. * plot/uipanel.m: Likewise. * plot/uimenu.m: Rewrite to use __uiobject_split_args__. * plot/uicontextmenu.m: New file. * plot/uitoolbar.m: Likewise. * plot/uipushtool.m: Likewise. * plot/uitoggletool.m: Likewise. * plot/modules.mk (plot_FCN_FILES): Add uicontextmenu.m, uitoolbar.m, uipushtool.m and uitoggletool.m.

--- a/scripts/plot/uicontrol.m
+++ b/scripts/plot/uicontrol.m
@@ -29,7 +29,7 @@
   if (nargin == 1 && ishandle (varargin{1}) && strcmpi (get (varargin{1}, "type"), "uicontrol"))
     error ("uicontrol focusing not implemented yet.");
   else
-    [h, args] = __uiobject_split_args__ ("uicontrol", varargin{:});
+    [h, args] = __uiobject_split_args__ ("uicontrol", varargin, {"figure", "uipanel", "uibuttongroup"});
     handle = __go_uicontrol__ (h, args{:});
   endif