From 58c763144d5381170f074336d522705b4ca93f7e Mon Sep 17 00:00:00 2001
From: cyantree - Christoph Schreiber <mail@cyantree.com>
Date: Fri, 3 Jul 2020 11:42:51 +0200
Subject: [PATCH] Support empty layers in `isValidShortKeyInternal()` which
 aren't the topmost layer

---
 src/js/game/shape_definition.js | 5 +++--
 1 file changed, 3 insertions(+), 2 deletions(-)

diff --git a/src/js/game/shape_definition.js b/src/js/game/shape_definition.js
index a521930f..33209bc9 100644
--- a/src/js/game/shape_definition.js
+++ b/src/js/game/shape_definition.js
@@ -220,10 +220,11 @@ export class ShapeDefinition extends BasicSerializableObject {
                 }
             }
 
-            if (!anyFilled) {
-                // Empty layer
+            if (!anyFilled && i === sourceLayers.length - 1) {
+                // Topmost layer isn't allowed being empty
                 return false;
             }
+
             layers.push(quads);
         }