[gtk/matthiasc/for-master: 5/5] keynav: Fix Shift-Tab

[Matthias Clasen <matthiasc src gnome org>]

commit dc3d778e01ada20ce13a85f14165740a797d7484
Author: Matthias Clasen <mclasen redhat com>
Date:   Wed Apr 1 00:21:19 2020 -0400

    keynav: Fix Shift-Tab
    
    This was broken by the shortcuts branch merge.

 gtk/gtkshortcuttrigger.c | 7 ++++++-
 1 file changed, 6 insertions(+), 1 deletion(-)
---
diff --git a/gtk/gtkshortcuttrigger.c b/gtk/gtkshortcuttrigger.c
index 0fdc5edb17..8be4bd3349 100644
--- a/gtk/gtkshortcuttrigger.c
+++ b/gtk/gtkshortcuttrigger.c
@@ -578,7 +578,12 @@ gtk_keyval_trigger_trigger (GtkShortcutTrigger *trigger,
        */
       key = self->keyval;
       if (self->modifiers & GDK_SHIFT_MASK)
-        key = gdk_keyval_to_upper (key);
+        {
+          if (key == GDK_KEY_Tab)
+            key = GDK_KEY_ISO_Left_Tab;
+          else
+            key = gdk_keyval_to_upper (key);
+        }
 
       if (keyval == key && /* exact match */
           (!group_mod_is_accel_mod ||