Fix FilePilot preview toggle after copy path

QuickLook.Native/QuickLook.Native32/FilePilot.cpp

@@ -27,6 +27,12 @@ namespace
     constexpr auto CLIPBOARD_POLL_INTERVAL_MS = 5;
     constexpr auto MAX_CLASS_NAME_LENGTH = 256;
 
+    // Tag synthetic key events generated by QuickLook (SendInput path) for
+    // third-party file manager interoperability. The managed low-level hook uses
+    // this marker to recognize and bypass these replayed keys.
+    // 0x514C5452 == 'QLTR' (QuickLook Third-party Replay)
+    constexpr ULONG_PTR QUICKLOOK_THIRD_PARTY_HOTKEY_REPLAY_EXTRA_INFO = 0x514C5452;
+
     bool StartsWith(PCWSTR value, PCWSTR prefix)
     {
         return wcsncmp(value, prefix, wcslen(prefix)) == 0;
@@ -183,24 +189,30 @@ namespace
 
         inputs[0].type = INPUT_KEYBOARD;
         inputs[0].ki.wVk = VK_CONTROL;
+        inputs[0].ki.dwExtraInfo = QUICKLOOK_THIRD_PARTY_HOTKEY_REPLAY_EXTRA_INFO;
 
         inputs[1].type = INPUT_KEYBOARD;
         inputs[1].ki.wVk = VK_SHIFT;
+        inputs[1].ki.dwExtraInfo = QUICKLOOK_THIRD_PARTY_HOTKEY_REPLAY_EXTRA_INFO;
 
         inputs[2].type = INPUT_KEYBOARD;
         inputs[2].ki.wVk = L'C';
+        inputs[2].ki.dwExtraInfo = QUICKLOOK_THIRD_PARTY_HOTKEY_REPLAY_EXTRA_INFO;
 
         inputs[3].type = INPUT_KEYBOARD;
         inputs[3].ki.wVk = L'C';
         inputs[3].ki.dwFlags = KEYEVENTF_KEYUP;
+        inputs[3].ki.dwExtraInfo = QUICKLOOK_THIRD_PARTY_HOTKEY_REPLAY_EXTRA_INFO;
 
         inputs[4].type = INPUT_KEYBOARD;
         inputs[4].ki.wVk = VK_SHIFT;
         inputs[4].ki.dwFlags = KEYEVENTF_KEYUP;
+        inputs[4].ki.dwExtraInfo = QUICKLOOK_THIRD_PARTY_HOTKEY_REPLAY_EXTRA_INFO;
 
         inputs[5].type = INPUT_KEYBOARD;
         inputs[5].ki.wVk = VK_CONTROL;
         inputs[5].ki.dwFlags = KEYEVENTF_KEYUP;
+        inputs[5].ki.dwExtraInfo = QUICKLOOK_THIRD_PARTY_HOTKEY_REPLAY_EXTRA_INFO;
 
         SendInput(_countof(inputs), inputs, sizeof(INPUT));
     }

QuickLook/Helpers/GlobalKeyboardHook.cs

@@ -28,6 +28,15 @@ internal class GlobalKeyboardHook : IDisposable
 {
     private static GlobalKeyboardHook _instance;
 
+    // Marker written to INPUT::dwExtraInfo for synthetic hotkeys replayed by QuickLook
+    // through SendInput when integrating with third-party file managers.
+    //
+    // The low-level keyboard hook checks this value and immediately forwards the event,
+    // so QuickLook does not treat its own replayed keystrokes as real user input.
+    // This prevents false invalid-key suppression and accidental preview state changes.
+    // 0x514C5452 == 'QLTR' (QuickLook Third-party Replay)
+    public const int QUICKLOOK_THIRD_PARTY_HOTKEY_REPLAY_EXTRA_INFO = 0x514C5452;
+
     private User32.KeyboardHookProc _callback;
     private nint _hHook = IntPtr.Zero;
 
@@ -77,6 +86,13 @@ private int HookProc(int code, int wParam, ref User32.KeyboardHookStruct lParam)
         if (IsWindowsKeyPressed())
             return User32.CallNextHookEx(_hHook, code, wParam, ref lParam);
 
+        // QuickLook itself may replay third-party hotkeys through SendInput.
+        // These events are tagged in dwExtraInfo and must be forwarded without
+        // entering QuickLook's hotkey pipeline, otherwise they can pollute state
+        // (for example invalid-key timing windows) and cause false toggles.
+        if (lParam.dwExtraInfo == User32.QUICKLOOK_THIRD_PARTY_HOTKEY_REPLAY_EXTRA_INFO)
+            return User32.CallNextHookEx(_hHook, code, wParam, ref lParam);
+
         var key = (Keys)lParam.vkCode;
         key = AddModifiers(key);