[gimp] app: remove focusability of toolbox buttons.

[Jehan Pagès <jehanp src gnome org>]

commit 52ad5bb2a11e39ffe714b5b3ba1f3be0aa305e7f
Author: Jehan <jehan girinstud io>
Date:   Mon Nov 28 15:52:42 2016 +0100

    app: remove focusability of toolbox buttons.
    
    Commit c83ee61 got overridded by commit b5cc2a9.
    Reintroducing the changes.

 app/widgets/gimptoolpalette.c |    7 +++++++
 1 files changed, 7 insertions(+), 0 deletions(-)
---
diff --git a/app/widgets/gimptoolpalette.c b/app/widgets/gimptoolpalette.c
index c23d0f9..76c8bc7 100644
--- a/app/widgets/gimptoolpalette.c
+++ b/app/widgets/gimptoolpalette.c
@@ -254,6 +254,13 @@ gimp_tool_palette_hierarchy_changed (GtkWidget *widget,
           else
             gimp_help_set_help_data (GTK_WIDGET (item),
                                      tool_info->help, tool_info->help_id);
+
+          /* Make sure the toolbox buttons won't grab focus, which has
+           * nearly no practical use, and prevents various actions until
+           * you click back in canvas.
+           */
+          gtk_widget_set_can_focus (gtk_bin_get_child (GTK_BIN (item)),
+                                    FALSE);
         }
     }
 }