diff --git a/js/ui/workspace.js b/js/ui/workspace.js
index ebf3d9ba3..60e0d44a8 100644
--- a/js/ui/workspace.js
+++ b/js/ui/workspace.js
@@ -628,7 +628,6 @@ var WorkspaceLayout = GObject.registerClass({
         const [containerWidth, containerHeight] = containerBox.get_size();
         const containerAllocationChanged =
             this._lastBox === null || !this._lastBox.equal(containerBox);
-        this._lastBox = containerBox.copy();
 
         // If the containers size changed, we can no longer keep around
         // the old windowSlots, so we must unfreeze the layout.
@@ -665,7 +664,7 @@ var WorkspaceLayout = GObject.registerClass({
         }
 
         let layoutChanged = false;
-        if (!this._layoutFrozen || this._needsLayout) {
+        if (!this._layoutFrozen || !this._lastBox) {
             if (this._needsLayout) {
                 this._layout = this._createBestLayout(this._workarea);
                 this._needsLayout = false;
@@ -765,6 +764,8 @@ var WorkspaceLayout = GObject.registerClass({
                 child.allocate(childBox);
             }
         }
+
+        this._lastBox = containerBox.copy();
     }
 
     _syncOverlay(preview) {