[gimp] app: GimpColorDialog follows the user context active image.

[Jehan <jehanp src gnome org>]

commit 425eb83f8a9bc27e2f93e65b337088dff5e6e2d0
Author: Jehan <jehan girinstud io>
Date:   Tue Mar 19 13:37:18 2019 +0100

    app: GimpColorDialog follows the user context active image.
    
    (when working in context-aware mode)

 app/widgets/gimpcolordialog.c | 11 ++++++++---
 1 file changed, 8 insertions(+), 3 deletions(-)
---
diff --git a/app/widgets/gimpcolordialog.c b/app/widgets/gimpcolordialog.c
index 918dbfb0aa..83d701f3f4 100644
--- a/app/widgets/gimpcolordialog.c
+++ b/app/widgets/gimpcolordialog.c
@@ -355,7 +355,11 @@ gimp_color_dialog_response (GtkDialog *gtk_dialog,
   col_index = gimp_colormap_selection_get_index (colormap_selection, NULL);
 
   if (dialog->colormap_editing && viewable_dialog->context)
-    image = gimp_context_get_image (viewable_dialog->context);
+    {
+      GimpContext *user_context = viewable_dialog->context->gimp->user_context;
+
+      image = gimp_context_get_image (user_context);
+    }
 
   switch (response_id)
     {
@@ -622,9 +626,10 @@ gimp_color_dialog_color_changed (GimpColorSelection *selection,
 
   if (dialog->colormap_editing && viewable_dialog->context)
     {
-      GimpImage *image;
+      GimpContext *user_context = viewable_dialog->context->gimp->user_context;
+      GimpImage   *image;
 
-      image = gimp_context_get_image (viewable_dialog->context);
+      image = gimp_context_get_image (user_context);
       if (image)
         {
           GimpColormapSelection *colormap_selection;