diff --git a/windowing/src/main/java/de/staropensource/engine/windowing/implementable/Window.java b/windowing/src/main/java/de/staropensource/engine/windowing/implementable/Window.java
index fc04f66e..d596bc9a 100644
--- a/windowing/src/main/java/de/staropensource/engine/windowing/implementable/Window.java
+++ b/windowing/src/main/java/de/staropensource/engine/windowing/implementable/Window.java
@@ -30,9 +30,7 @@ import lombok.Setter;
 import org.jetbrains.annotations.NotNull;
 import org.jetbrains.annotations.Nullable;
 
-import java.util.HashSet;
-import java.util.Set;
-import java.util.UUID;
+import java.util.*;
 
 /**
  * Abstract class for implementing windows in a windowing API.
@@ -43,16 +41,15 @@ import java.util.UUID;
  *
  * @since v1-alpha0
  */
-// TODO monitors
 @Getter
 @SuppressWarnings({ "JavadocDeclaration" })
 public abstract class Window implements AutoCloseable {
     /**
      * A set of all active windows.
      *
-     * @since v1-alpha0
+     * @since v1-alpha6
      */
-    private static final @NotNull Set<@NotNull Window> windows = new HashSet<>();
+    private static final @NotNull List<@NotNull Window> windows = new ArrayList<>();
 
     /**
      * Contains the {@link LoggerInstance} for this instance.