[gimp/gtk3-port: 361/457] app: fix empty display unstable-version message

[Michael Natterer <mitch src gnome org>]

commit a1e4f2426472e6923109e70e3c2c1d0d865cdcb7
Author: Ell <ell_se yahoo com>
Date:   Sun May 6 18:22:39 2018 -0400

    app: fix empty display unstable-version message

 app/display/gimpdisplayshell-callbacks.c |   19 +++++++++++++------
 1 files changed, 13 insertions(+), 6 deletions(-)
---
diff --git a/app/display/gimpdisplayshell-callbacks.c b/app/display/gimpdisplayshell-callbacks.c
index 38e60a3..7a2afd1 100644
--- a/app/display/gimpdisplayshell-callbacks.c
+++ b/app/display/gimpdisplayshell-callbacks.c
@@ -525,12 +525,16 @@ gimp_display_shell_canvas_draw_drop_zone (GimpDisplayShell *shell,
 
 #ifdef GIMP_UNSTABLE
   {
-    PangoLayout   *layout;
-    gchar         *msg;
-    GtkAllocation  allocation;
-    gint           width;
-    gint           height;
-    gdouble        scale;
+    GtkWidget       *widget  = GTK_WIDGET (shell);
+    GtkStyleContext *context = gtk_widget_get_style_context (widget);
+    GtkStateFlags    state   = gtk_widget_get_state_flags (widget);
+    PangoLayout     *layout;
+    gchar           *msg;
+    GtkAllocation    allocation;
+    gint             width;
+    gint             height;
+    gdouble          scale;
+    GdkRGBA          color;
 
     layout = gtk_widget_create_pango_layout (shell->canvas, NULL);
 
@@ -550,6 +554,9 @@ gimp_display_shell_canvas_draw_drop_zone (GimpDisplayShell *shell,
     scale = MIN (((gdouble) allocation.width  / 2.0) / (gdouble) width,
                  ((gdouble) allocation.height / 2.0) / (gdouble) height);
 
+    gtk_style_context_get_color (context, state, &color);
+    gdk_cairo_set_source_rgba (cr, &color);
+
     cairo_move_to (cr,
                    (allocation.width  - (width  * scale)) / 2,
                    (allocation.height - (height * scale)) / 2);