From a2c836ff348164facc84fe5af5d08e2b5806f36b Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Tor=20Hedin=20Br=C3=B8nner?= <torhedinbronner@gmail.com>
Date: Tue, 3 Oct 2017 01:46:40 +0200
Subject: [PATCH] Don't try to preview worksapces that doesn't exist

---
 tiling.js | 4 ++++
 1 file changed, 4 insertions(+)

diff --git a/tiling.js b/tiling.js
index f4e0e85..d515938 100644
--- a/tiling.js
+++ b/tiling.js
@@ -721,6 +721,8 @@ PreviewedWindowNavigator = new Lang.Class({
             let multimap = this._switcherList.actor;
             let from = multimap.selectedIndex;
             let to = from - 1;
+            if (to < 0)
+                return;
             Main.wm._previewWorkspaceDone();
             Main.wm._previewWorkspace(from, to, Meta.MotionDirection.UP);
             multimap.setSelected(to);
@@ -733,6 +735,8 @@ PreviewedWindowNavigator = new Lang.Class({
             let multimap = this._switcherList.actor;
             let from = multimap.selectedIndex;
             let to = from + 1;
+            if (to >= spaces.length)
+                return;
             Main.wm._previewWorkspaceDone();
             Main.wm._previewWorkspace(from, to, Meta.MotionDirection.DOWN);
             multimap.setSelected(to);