diff --git a/src/MaaWpfGui/Helper/StageManager.cs b/src/MaaWpfGui/Helper/StageManager.cs
index a87b9e21f3..564f822adc 100644
--- a/src/MaaWpfGui/Helper/StageManager.cs
+++ b/src/MaaWpfGui/Helper/StageManager.cs
@@ -214,6 +214,11 @@ namespace MaaWpfGui
         /// <returns>Whether stage is open</returns>
         public bool IsStageOpen(string stage, DayOfWeek dayOfWeek)
         {
+            if (stage == null)
+            {
+                return false;
+            }
+
             return GetStageInfo(stage)?.IsStageOpen(dayOfWeek) == true;
         }
 
diff --git a/src/MaaWpfGui/Main/TaskQueueViewModel.cs b/src/MaaWpfGui/Main/TaskQueueViewModel.cs
index 948b8ac48b..a969a5af25 100644
--- a/src/MaaWpfGui/Main/TaskQueueViewModel.cs
+++ b/src/MaaWpfGui/Main/TaskQueueViewModel.cs
@@ -279,13 +279,13 @@ namespace MaaWpfGui
             if (settingsModel.HideUnavailableStage)
             {
                 // update available stage list
-                var stage1 = Stage1;
+                var stage1 = Stage1 ??= string.Empty;
                 StageList = new ObservableCollection<CombData>(_stageManager.GetStageList(_curDayOfWeek));
 
                 // reset closed stage1 to "Last/Current"
                 if (!CustomStageCode)
                 {
-                    Stage1 = (stage1 != null && _stageManager.IsStageOpen(stage1, _curDayOfWeek)) ? stage1 : string.Empty;
+                    Stage1 = _stageManager.IsStageOpen(stage1, _curDayOfWeek) ? stage1 : string.Empty;
                 }
             }
             else
@@ -293,23 +293,25 @@ namespace MaaWpfGui
                 // initializing or settings changing, update stage list forcely
                 if (forceUpdate)
                 {
-                    var stage1 = Stage1;
-                    var stage2 = Stage2;
-                    var stage3 = Stage3;
+                    var stage1 = Stage1 ??= string.Empty;
+                    var stage2 = Stage2 ??= string.Empty;
+                    var stage3 = Stage3 ??= string.Empty;
 
                     StageList = new ObservableCollection<CombData>(_stageManager.GetStageList());
 
                     // reset closed stages to "Last/Current"
                     if (!CustomStageCode)
                     {
+                        EnableSetFightParams = false;
                         Stage1 = StageList.Any(x => x.Value == stage1) ? stage1 : string.Empty;
                         Stage2 = StageList.Any(x => x.Value == stage2) ? stage2 : string.Empty;
                         Stage3 = StageList.Any(x => x.Value == stage3) ? stage3 : string.Empty;
+                        EnableSetFightParams = true;
                     }
                 }
             }
 
-            var rss = RemainingSanityStage;
+            var rss = RemainingSanityStage ??= string.Empty;
             RemainingSanityStageList = new ObservableCollection<CombData>(_stageManager.GetStageList())
             {
                 [0] = new CombData { Display = Localization.GetString("NoUse"), Value = string.Empty },
@@ -774,49 +776,54 @@ namespace MaaWpfGui
             return asstProxy.AsstAppendFight(RemainingSanityStage, 0, 0, int.MaxValue, string.Empty, 0, false);
         }
 
+        public bool EnableSetFightParams { get; set; } = true;
+
         /// <summary>
         /// Sets parameters.
         /// </summary>
         public void SetFightParams()
         {
-            int medicine = 0;
-            if (UseMedicine)
+            if (EnableSetFightParams)
             {
-                if (!int.TryParse(MedicineNumber, out medicine))
+                int medicine = 0;
+                if (UseMedicine)
                 {
-                    medicine = 0;
+                    if (!int.TryParse(MedicineNumber, out medicine))
+                    {
+                        medicine = 0;
+                    }
                 }
-            }
 
-            int stone = 0;
-            if (UseStone)
-            {
-                if (!int.TryParse(StoneNumber, out stone))
+                int stone = 0;
+                if (UseStone)
                 {
-                    stone = 0;
+                    if (!int.TryParse(StoneNumber, out stone))
+                    {
+                        stone = 0;
+                    }
                 }
-            }
 
-            int times = int.MaxValue;
-            if (HasTimesLimited)
-            {
-                if (!int.TryParse(MaxTimes, out times))
+                int times = int.MaxValue;
+                if (HasTimesLimited)
                 {
-                    times = 0;
+                    if (!int.TryParse(MaxTimes, out times))
+                    {
+                        times = 0;
+                    }
                 }
-            }
 
-            int drops_quantity = 0;
-            if (IsSpecifiedDrops)
-            {
-                if (!int.TryParse(DropsQuantity, out drops_quantity))
+                int drops_quantity = 0;
+                if (IsSpecifiedDrops)
                 {
-                    drops_quantity = 0;
+                    if (!int.TryParse(DropsQuantity, out drops_quantity))
+                    {
+                        drops_quantity = 0;
+                    }
                 }
-            }
 
-            var asstProxy = _container.Get<AsstProxy>();
-            asstProxy.AsstSetFightTaskParams(Stage, medicine, stone, times, DropsItemId, drops_quantity);
+                var asstProxy = _container.Get<AsstProxy>();
+                asstProxy.AsstSetFightTaskParams(Stage, medicine, stone, times, DropsItemId, drops_quantity);
+            }
         }
 
         public void SetFightRemainingSanityParams()