[iagno] Small improvement.

[Arnaud B. <arnaudb src gnome org>]

commit 2a3add23c750edf7026f39ba42117911fc6c4613
Author: Arnaud Bonatti <arnaud bonatti gmail com>
Date:   Mon Oct 14 10:09:55 2019 +0200

    Small improvement.

 src/reversi-view.vala | 2 ++
 1 file changed, 2 insertions(+)
---
diff --git a/src/reversi-view.vala b/src/reversi-view.vala
index 097c8a8..3889508 100644
--- a/src/reversi-view.vala
+++ b/src/reversi-view.vala
@@ -1263,6 +1263,8 @@ private class ReversiView : Gtk.DrawingArea
             return false;
 
         string key = (!) (Gdk.keyval_name (event.keyval) ?? "");
+        if (key == "")
+            return false;
 
         if (show_highlight && (key == "space" || key == "Return" || key == "KP_Enter"))
         {