[gimp] app: add a tooltip to the layer mode group combo

[Michael Natterer <mitch src gnome org>]

commit 51709803095865f79afb9eb987a08bb6bf2e139e
Author: Michael Natterer <mitch gimp org>
Date:   Mon Jan 30 14:02:35 2017 +0100

    app: add a tooltip to the layer mode group combo

 app/widgets/gimplayermodebox.c |    4 ++++
 1 files changed, 4 insertions(+), 0 deletions(-)
---
diff --git a/app/widgets/gimplayermodebox.c b/app/widgets/gimplayermodebox.c
index fcf7737..7ae6f55 100644
--- a/app/widgets/gimplayermodebox.c
+++ b/app/widgets/gimplayermodebox.c
@@ -158,6 +158,10 @@ gimp_layer_mode_box_constructed (GObject *object)
   gtk_box_pack_start (GTK_BOX (box), group_combo, FALSE, FALSE, 0);
   gtk_widget_show (group_combo);
 
+  gimp_help_set_help_data (group_combo,
+                           _("Switch to another group of modes"),
+                           NULL);
+
   layout = GTK_CELL_LAYOUT (gtk_bin_get_child (GTK_BIN (group_combo)));
   gtk_cell_layout_clear (layout);