diff --git a/storage/itemgroup.lua b/storage/itemgroup.lua
index 955410b..55eb919 100644
--- a/storage/itemgroup.lua
+++ b/storage/itemgroup.lua
@@ -33,6 +33,14 @@ function ItemGroup:getDisplayName()
   return self:_getIdentityStack():getDisplayName()
 end
 
+function ItemGroup:getSimpleName()
+  return self:isEmpty() and "[EMPTY]" or self:_getIdentityStack():getSimpleName()
+end
+
+function ItemGroup:isEmpty()
+  return self:_getIdentityStack():isEmpty()
+end
+
 function ItemGroup:getName()
   return self:_getIdentityStack():getName()
 end