diff --git a/InvUI/src/main/java/de/studiocode/invui/gui/impl/BaseGUI.java b/InvUI/src/main/java/de/studiocode/invui/gui/impl/BaseGUI.java
index 2c57a0c..378f7d0 100644
--- a/InvUI/src/main/java/de/studiocode/invui/gui/impl/BaseGUI.java
+++ b/InvUI/src/main/java/de/studiocode/invui/gui/impl/BaseGUI.java
@@ -526,7 +526,7 @@ public abstract class BaseGUI implements GUI, Controllable {
     @Override
     public void addItems(@NotNull Item... items) {
         for (Item item : items) {
-            int emptyIndex = ArrayUtils.findFirstEmptyIndex(items);
+            int emptyIndex = ArrayUtils.findFirstEmptyIndex(slotElements);
             if (emptyIndex == -1) break;
             setItem(emptyIndex, item);
         }