From 68ec95f554bc782fb7f818583f68516a7fe7352d Mon Sep 17 00:00:00 2001
From: Centronias <me@centronias.com>
Date: Sun, 16 Aug 2026 22:38:14 +0000
Subject: [PATCH] Fix UI Window Memory Leak in `CloseRecentWindowUIController`
 (#45399)

no leaking windows
---
 .../Systems/CloseWindow/CloseRecentWindowUIController.cs | 9 +++++++++
 1 file changed, 9 insertions(+)

diff --git a/Content.Client/UserInterface/Systems/CloseWindow/CloseRecentWindowUIController.cs b/Content.Client/UserInterface/Systems/CloseWindow/CloseRecentWindowUIController.cs
index 8d3e7594ef..f15b235210 100644
--- a/Content.Client/UserInterface/Systems/CloseWindow/CloseRecentWindowUIController.cs
+++ b/Content.Client/UserInterface/Systems/CloseWindow/CloseRecentWindowUIController.cs
@@ -27,6 +27,7 @@ public sealed partial class CloseRecentWindowUIController : UIController
         // (Does not need to be unlistened since UIControllers live forever)
         _uiManager.OnKeyBindDown += OnKeyBindDown;
         _uiManager.WindowRoot.OnChildAdded += OnRootChildAdded;
+        _uiManager.WindowRoot.OnChildRemoved += OnRootChildRemoved;
 
         _inputManager.SetInputCommand(EngineKeyFunctions.WindowCloseRecent,
             InputCmdHandler.FromDelegate(session => CloseMostRecentWindow()));
@@ -122,6 +123,14 @@ public sealed partial class CloseRecentWindowUIController : UIController
         }
     }
 
+    private void OnRootChildRemoved(Control control)
+    {
+        if (control is BaseWindow window)
+        {
+            recentlyInteractedWindows.Remove(window);
+        }
+    }
+
     /// <summary>
     /// Checks whether there are any windows that can be closed.
     /// </summary>