[gimp] app: do not allow Alt+[0-9] shortcuts.

[Jehan Pagès <jehanp src gnome org>]

commit 31ae4238d20a645670c273b1c533f56ad8caf065
Author: Jehan <jehan girinstud io>
Date:   Fri Nov 25 05:41:23 2016 +0100

    app: do not allow Alt+[0-9] shortcuts.
    
    These are used for display switching, and even though you could
    remap these shortcuts, it would work only until you close an image,
    open a new one, or reorder tabs in SWM, in which case your shortcut
    would end up forcefully overrided, which is a bad user experience.
    If we want to give more flexibility and allow one to map these
    shortcuts, we must also make sure the display showing actions won't
    override customized shortcuts. In the meantime, it is better to
    simply forbid these in our preferences.

 app/widgets/gimpactionview.c |   11 +++++++++++
 1 files changed, 11 insertions(+), 0 deletions(-)
---
diff --git a/app/widgets/gimpactionview.c b/app/widgets/gimpactionview.c
index fa40d0c..da872fb 100644
--- a/app/widgets/gimpactionview.c
+++ b/app/widgets/gimpactionview.c
@@ -795,6 +795,17 @@ gimp_action_view_accel_edited (GtkCellRendererAccel *accel,
                             G_OBJECT (view), GIMP_MESSAGE_ERROR,
                             _("F1 cannot be remapped."));
     }
+  else if (accel_key  >= GDK_KEY_0 &&
+           accel_key  <= GDK_KEY_9 &&
+           accel_mask == GDK_MOD1_MASK)
+    {
+      gimp_message (view->manager->gimp,
+                    G_OBJECT (view), GIMP_MESSAGE_ERROR,
+                    _("Alt+%d is used to switch to display %d and "
+                      "cannot be remapped."),
+                    accel_key - GDK_KEY_0,
+                    accel_key == GDK_KEY_0 ? 10 : accel_key - GDK_KEY_0);
+    }
   else if (! gtk_accel_map_change_entry (accel_path,
                                          accel_key, accel_mask, FALSE))
     {