[gimp] app: clear display filter stack when emptying a display

[N/A <ell src gnome org>]

commit d591bf51f023d22919aafec384534c38a4fc4851
Author: Ell <ell_se yahoo com>
Date:   Sun Nov 12 12:09:02 2017 -0500

    app: clear display filter stack when emptying a display

 app/display/gimpdisplayshell.c |    2 ++
 1 files changed, 2 insertions(+), 0 deletions(-)
---
diff --git a/app/display/gimpdisplayshell.c b/app/display/gimpdisplayshell.c
index 4c91f20..24b96b2 100644
--- a/app/display/gimpdisplayshell.c
+++ b/app/display/gimpdisplayshell.c
@@ -1434,6 +1434,8 @@ gimp_display_shell_empty (GimpDisplayShell *shell)
 
   gimp_display_shell_unset_cursor (shell);
 
+  gimp_display_shell_filter_set (shell, NULL);
+
   gimp_display_shell_sync_config (shell, shell->display->config);
 
   gimp_display_shell_appearance_update (shell);