NEG/UI/UiManager.cs

@@ -152,7 +152,8 @@ namespace NEG.UI
         {
             if(CurrentMainWindow != window)
                 return;
-            
+
+            CurrentMainWindow = null;
             //TODO: select new main window
         }
 

NEG/UI/UnityUi/Area/AutoOpenWindowWhenNoOther.cs

@@ -0,0 +1,17 @@
+using NEG.UI.UnityUi.Window;
+using NEG.UI.Window;
+using UnityEngine;
+
+namespace NEG.UI.Area
+{
+    public class AutoOpenWindowWhenNoOther : MonoBehaviour
+    {
+        [SerializeField] private MonoWindow window;
+
+        private void Start()
+        {
+            if(UiManager.Instance.CurrentMainWindow == null)
+                window.Open();
+        }
+    }
+}

NEG/UI/UnityUi/Area/AutoOpenWindowWhenNoOther.cs.meta

@@ -0,0 +1,3 @@
+fileFormatVersion: 2
+guid: 473c065573984067a824ebf3b605c3ab
+timeCreated: 1695048071

NEG/UI/UnityUi/Window/MonoWindow.cs

@@ -55,6 +55,12 @@ namespace NEG.UI.UnityUi.Window
 
         private void Awake() => ((IWindow)this).SetHiddenState();
 
+        private void OnDestroy()
+        {
+            if(gameObject.activeSelf)
+                UiManager.Instance.OnWindowClosed(this);
+        }
+
         private void OnValidate()
         {
             #if !NEG_UI_DISABLE_WARNING_DEFAULT_SELECTION