diff --git a/OPTIONS.md b/OPTIONS.md
index a5fd6b0cb..f09c27ec8 100644
--- a/OPTIONS.md
+++ b/OPTIONS.md
@@ -60,13 +60,6 @@ Example:
 - Example:
   - `<WindowBackgroundColor>#FFC0CB</WindowBackgroundColor>`
 
-### `<Topmost>`
-- Default: `False`
-- Type: `Boolean`
-- Description: Keep the preview window on top of other windows.
-- Example:
-  - `<Topmost>True</Topmost>`
-
 ### `<ShowInTaskbar>`
 - Default: `False`
 - Type: `Boolean`
diff --git a/QuickLook/ViewerWindow.xaml.cs b/QuickLook/ViewerWindow.xaml.cs
index 7eb190af7..e98145e86 100644
--- a/QuickLook/ViewerWindow.xaml.cs
+++ b/QuickLook/ViewerWindow.xaml.cs
@@ -67,8 +67,10 @@ internal ViewerWindow()
 
         windowFrameContainer.PreviewMouseMove += ShowWindowCaptionContainer;
 
-        Topmost = SettingHelper.Get("Topmost", false);
-        buttonTop.Tag = Topmost ? "Top" : "Auto";
+        // The preview window is always on top; the toggle button is hidden.
+        Topmost = true;
+        buttonTop.Tag = "Top";
+        buttonTop.Visibility = Visibility.Collapsed;
 
         ShowInTaskbar = SettingHelper.Get("ShowInTaskbar", false);
 
@@ -87,13 +89,6 @@ internal ViewerWindow()
             }, DispatcherPriority.ContextIdle);
         };
 
-        buttonTop.Click += (_, _) =>
-        {
-            Topmost = !Topmost;
-            SettingHelper.Set("Topmost", Topmost);
-            buttonTop.Tag = Topmost ? "Top" : "Auto";
-        };
-
         buttonPin.Click += (_, _) =>
         {
             if (SettingHelper.Get("CloseOnLostFocus", false))