[gimp] app: improve GimpFilterTool::can_pick()

[N/A <ell src gnome org>]

commit bd5ec4613b7902a05c55fb9629a52212cb6d0394
Author: Ell <ell_se yahoo com>
Date:   Wed May 3 14:46:39 2017 -0400

    app: improve GimpFilterTool::can_pick()
    
    Make sure the drawable we're about to pick from is actually the
    filter tool's drawable.

 app/tools/gimpfiltertool.c |    4 ++++
 1 files changed, 4 insertions(+), 0 deletions(-)
---
diff --git a/app/tools/gimpfiltertool.c b/app/tools/gimpfiltertool.c
index 51c24e5..f858f27 100644
--- a/app/tools/gimpfiltertool.c
+++ b/app/tools/gimpfiltertool.c
@@ -801,8 +801,12 @@ gimp_filter_tool_can_pick_color (GimpColorTool    *color_tool,
                                  GimpDisplay      *display)
 {
   GimpFilterTool *filter_tool = GIMP_FILTER_TOOL (color_tool);
+  GimpImage      *image       = gimp_display_get_image (display);
   gboolean        pick_abyss;
 
+  if (gimp_image_get_active_drawable (image) != filter_tool->drawable)
+    return FALSE;
+
   pick_abyss =
     GPOINTER_TO_INT (g_object_get_data (G_OBJECT (filter_tool->active_picker),
                      "picker-pick-abyss"));