diff --git a/liveAltTab.js b/liveAltTab.js
index f0a03d9..18daf4e 100644
--- a/liveAltTab.js
+++ b/liveAltTab.js
@@ -65,10 +65,10 @@ WindowManager.WindowManager.prototype._previewWorkspace = function(from, to, dir
             switchData.movingWindow = record;
             switchData.windows.push(switchData.movingWindow);
             actor.reparent(switchData.movingWindowBin);
-        } else if (window.get_workspace().index() == from) {
+        } else if (window.get_workspace() == from) {
             switchData.windows.push(record);
             actor.reparent(switchData.outGroup);
-        } else if (window.get_workspace().index() == to) {
+        } else if (window.get_workspace() == to) {
             switchData.windows.push(record);
             actor.reparent(switchData.inGroup);
             actor.show();
@@ -164,8 +164,8 @@ LiveAltTab = Lang.Class({
         let toIndex = to.get_workspace().workspace_index;
         if (toIndex !== fromIndex) {
             let direction = fromIndex < toIndex ? Meta.MotionDirection.DOWN : Meta.MotionDirection.UP;
-            Main.wm._previewWorkspace(from.get_workspace().workspace_index,
-                                      to.get_workspace().workspace_index,
+            Main.wm._previewWorkspace(from.get_workspace(),
+                                      to.get_workspace(),
                                       direction)
             this.switchedWorkspace = true;
         }
diff --git a/tiling.js b/tiling.js
index 8b674c2..932f618 100644
--- a/tiling.js
+++ b/tiling.js
@@ -866,8 +866,8 @@ PreviewedWindowNavigator = new Lang.Class({
         }
 
         // This will crash gnome-shell if one of the workspaces have been removed
-        Main.wm._previewWorkspace(oldMap.space.workspace.workspace_index,
-                                  newMap.space.workspace.workspace_index,
+        Main.wm._previewWorkspace(oldMap.space.workspace,
+                                  newMap.space.workspace,
                                   direction);
         this.space = newMap.space;
         this._select(this.space.selectedIndex());