diff --git a/HellionChat/Plugin.cs b/HellionChat/Plugin.cs
index 9204b5c..865b3dd 100755
--- a/HellionChat/Plugin.cs
+++ b/HellionChat/Plugin.cs
@@ -374,6 +374,7 @@ public sealed class Plugin : IAsyncDalamudPlugin
                 new SelfTests.HonorificHeaderRenderStep(this),
                 new SelfTests.PerformanceBaselineStep(this),
                 new SelfTests.MainWindowFocusOpacityStep(this),
+                new SelfTests.MainWindowFlagsStep(this),
             ]);
 
             // Re-surface the wizard for existing users when a major UX
diff --git a/HellionChat/SelfTests/MainWindowFlagsStep.cs b/HellionChat/SelfTests/MainWindowFlagsStep.cs
new file mode 100644
index 0000000..7a96ab9
--- /dev/null
+++ b/HellionChat/SelfTests/MainWindowFlagsStep.cs
@@ -0,0 +1,74 @@
+using Dalamud.Bindings.ImGui;
+using Dalamud.Plugin.SelfTest;
+using HellionChat.Ui.Windows;
+
+namespace HellionChat.SelfTests;
+
+// B1-2 window flags. Drives the REAL MainWindow.PreDraw and asserts it wired
+// Window.Flags to ResolveFlags(CanMove, CanResize), then pins the pure
+// fresh-base contract: false/false adds NoMove|NoResize, true/true clears them
+// (the masterplan's "flags must rebuild from a fresh base, else NoMove sticks
+// after toggling back" risk). NoScrollbar|NoScrollWithMouse always present.
+// Non-test caller of ResolveFlags: MainWindow.PreDraw.
+internal sealed class MainWindowFlagsStep : ISelfTestStep
+{
+    private readonly Plugin plugin;
+
+    public MainWindowFlagsStep(Plugin plugin)
+    {
+        this.plugin = plugin;
+    }
+
+    public string Name => "Hellion Chat - MainWindow flags";
+
+    public SelfTestStepResult RunStep()
+    {
+        var window = this.plugin.MainWindow;
+        if (window is null)
+        {
+            ImGui.Text("Plugin.MainWindow is null");
+            return SelfTestStepResult.Fail;
+        }
+
+        // Wiring proof: drive the real PreDraw and confirm Flags == the helper's
+        // value for the live config. No state mutation needed.
+        var savedFlags = window.Flags;
+        window.PreDraw();
+        var expected = MainWindow.ResolveFlags(Plugin.Config.CanMove, Plugin.Config.CanResize);
+        if (window.Flags != expected)
+        {
+            ImGui.Text($"PreDraw set Flags {window.Flags}, expected ResolveFlags = {expected}");
+            window.Flags = savedFlags;
+            return SelfTestStepResult.Fail;
+        }
+
+        // Fresh-base contract: locked window carries NoMove|NoResize ...
+        var locked = MainWindow.ResolveFlags(false, false);
+        if (
+            !locked.HasFlag(ImGuiWindowFlags.NoMove)
+            || !locked.HasFlag(ImGuiWindowFlags.NoResize)
+            || !locked.HasFlag(ImGuiWindowFlags.NoScrollbar)
+        )
+        {
+            ImGui.Text(
+                $"ResolveFlags(false,false) = {locked}, missing NoMove/NoResize/NoScrollbar"
+            );
+            window.Flags = savedFlags;
+            return SelfTestStepResult.Fail;
+        }
+
+        // ... and re-enabling both CLEARS NoMove|NoResize (no accumulation).
+        var free = MainWindow.ResolveFlags(true, true);
+        if (free.HasFlag(ImGuiWindowFlags.NoMove) || free.HasFlag(ImGuiWindowFlags.NoResize))
+        {
+            ImGui.Text($"ResolveFlags(true,true) = {free}, NoMove/NoResize stuck after re-enable");
+            window.Flags = savedFlags;
+            return SelfTestStepResult.Fail;
+        }
+
+        window.Flags = savedFlags;
+        return SelfTestStepResult.Pass;
+    }
+
+    public void CleanUp() { }
+}
diff --git a/HellionChat/Ui/Components/Settings/Tabs/GeneralTab.cs b/HellionChat/Ui/Components/Settings/Tabs/GeneralTab.cs
index 55af53a..740ada3 100644
--- a/HellionChat/Ui/Components/Settings/Tabs/GeneralTab.cs
+++ b/HellionChat/Ui/Components/Settings/Tabs/GeneralTab.cs
@@ -15,16 +15,6 @@ internal sealed class GeneralTab
     {
         if (ImGui.CollapsingHeader("Behavior", ImGuiTreeNodeFlags.DefaultOpen))
         {
-            DrawToggle(
-                "Allow window movement",
-                () => Plugin.Config.CanMove,
-                v => Plugin.Config.CanMove = v
-            );
-            DrawToggle(
-                "Allow window resize",
-                () => Plugin.Config.CanResize,
-                v => Plugin.Config.CanResize = v
-            );
             DrawToggle(
                 "Reduce motion (no theme crossfade)",
                 () => Plugin.Config.ReduceMotion,
diff --git a/HellionChat/Ui/Components/Settings/Tabs/WindowTab.cs b/HellionChat/Ui/Components/Settings/Tabs/WindowTab.cs
index 0da2b9c..17638e0 100644
--- a/HellionChat/Ui/Components/Settings/Tabs/WindowTab.cs
+++ b/HellionChat/Ui/Components/Settings/Tabs/WindowTab.cs
@@ -48,6 +48,11 @@ internal sealed class WindowTab
 
         if (ImGui.CollapsingHeader("Resize behavior", ImGuiTreeNodeFlags.DefaultOpen))
         {
+            DrawToggle(
+                "Allow movement",
+                () => Plugin.Config.CanMove,
+                v => Plugin.Config.CanMove = v
+            );
             DrawToggle(
                 "Allow resize",
                 () => Plugin.Config.CanResize,
diff --git a/HellionChat/Ui/Windows/MainWindow.cs b/HellionChat/Ui/Windows/MainWindow.cs
index cecf4d2..8df6df8 100644
--- a/HellionChat/Ui/Windows/MainWindow.cs
+++ b/HellionChat/Ui/Windows/MainWindow.cs
@@ -66,9 +66,6 @@ internal sealed class MainWindow : Window
             MinimumSize = new Vector2(MinWidth, MinHeight),
             MaximumSize = new Vector2(float.MaxValue, float.MaxValue),
         };
-        // The message list owns its own scroll inside the body child;
-        // the outer window must not show a second scrollbar.
-        Flags = ImGuiWindowFlags.NoScrollbar | ImGuiWindowFlags.NoScrollWithMouse;
         IsOpen = Plugin.Config.MainWindowOpen;
         RespectCloseHotkey = false;
     }
@@ -80,6 +77,22 @@ internal sealed class MainWindow : Window
     internal float ResolveBgAlpha(bool isFocused) =>
         isFocused ? Plugin.Config.WindowOpacity : Plugin.Config.WindowOpacityInactive;
 
+    // B1-2: rebuild flags from a fresh base every frame so toggling CanMove/
+    // CanResize back on actually CLEARS NoMove/NoResize (not accumulating).
+    // Move/resize toggle logic as 1.5.6 (ChatLogWindow.PreOpenCheck
+    // 1d3b429:703-707); base flags = today's MainWindow set (NoScrollbar|
+    // NoScrollWithMouse — the message list owns its own scroll; 1.5.6's
+    // NoFocusOnAppearing/NoTitleBar are deliberately not restored).
+    internal static ImGuiWindowFlags ResolveFlags(bool canMove, bool canResize)
+    {
+        var flags = ImGuiWindowFlags.NoScrollbar | ImGuiWindowFlags.NoScrollWithMouse;
+        if (!canMove)
+            flags |= ImGuiWindowFlags.NoMove;
+        if (!canResize)
+            flags |= ImGuiWindowFlags.NoResize;
+        return flags;
+    }
+
     public override void PreDraw()
     {
         // Dalamud's WindowHost turns Window.BgAlpha into SetNextWindowBgAlpha
@@ -100,6 +113,8 @@ internal sealed class MainWindow : Window
             else
                 BgAlpha = null;
         }
+
+        Flags = ResolveFlags(Plugin.Config.CanMove, Plugin.Config.CanResize);
     }
 
     public Tab? ActiveTab => _activeTab;