[gimp] app: do not add both a GtkLabel and GtkImage child to a GtkCheckButton.

[Jehan Pagès <jehanp src gnome org>]

commit e6f4dad28c1e763e877cb6158ea5e507cf4a400b
Author: Jehan <jehan girinstud io>
Date:   Thu Feb 11 15:54:36 2016 +0100

    app: do not add both a GtkLabel and GtkImage child to a GtkCheckButton.
    
    Since commit 9c4dd96, a NULL label to gimp_prop_check_button_new()
    generates a label from the property nick. Trying to add a GtkImage in
    the button outputs a warning because a GtkBin can have only one child.
    Fixes the warning:
    Gtk-WARNING **: Attempting to add a widget with type GtkImage to a
    GtkCheckButton, but as a GtkBin subclass a GtkCheckButton can only contain one
    widget at a time; it already contains a widget of type GtkLabel

 app/widgets/gimpviewablebox.c |    4 ++++
 1 files changed, 4 insertions(+), 0 deletions(-)
---
diff --git a/app/widgets/gimpviewablebox.c b/app/widgets/gimpviewablebox.c
index 6fdc7b0..ce40644 100644
--- a/app/widgets/gimpviewablebox.c
+++ b/app/widgets/gimpviewablebox.c
@@ -374,6 +374,10 @@ gradient_box_new (GimpContainer *container,
 
       image = gtk_image_new_from_icon_name (GIMP_STOCK_FLIP_HORIZONTAL,
                                             GTK_ICON_SIZE_MENU);
+      /* gimp_prop_check_button_new() adds the property nick as label of
+       * the button by default. */
+      gtk_container_remove (GTK_CONTAINER (toggle),
+                            gtk_bin_get_child (GTK_BIN (toggle)));
       gtk_container_add (GTK_CONTAINER (toggle), image);
       gtk_widget_show (image);