diff --git a/dll/ime/msctfime/CMakeLists.txt b/dll/ime/msctfime/CMakeLists.txt
index 10f18eab2d0..3dea866e674 100644
--- a/dll/ime/msctfime/CMakeLists.txt
+++ b/dll/ime/msctfime/CMakeLists.txt
@@ -17,5 +17,5 @@ add_library(msctfime MODULE
 set_module_type(msctfime win32dll UNICODE)
 set_target_properties(msctfime PROPERTIES SUFFIX ".ime")
 target_link_libraries(msctfime wine uuid)
-add_importlibs(msctfime user32 gdi32 advapi32 comctl32 msvcrt kernel32 ntdll)
+add_importlibs(msctfime imm32 user32 gdi32 advapi32 comctl32 msvcrt kernel32 ntdll)
 add_cd_file(TARGET msctfime DESTINATION reactos/system32 FOR all)
diff --git a/dll/ime/msctfime/msctfime.cpp b/dll/ime/msctfime/msctfime.cpp
index 8bf27f62d61..2b6404f4819 100644
--- a/dll/ime/msctfime/msctfime.cpp
+++ b/dll/ime/msctfime/msctfime.cpp
@@ -766,14 +766,29 @@ CtfImeGetGuidAtom(
     return E_FAIL;
 }
 
+/***********************************************************************
+ *      CtfImeIsGuidMapEnable (MSCTFIME.@)
+ *
+ * @implemented
+ */
 EXTERN_C BOOL WINAPI
 CtfImeIsGuidMapEnable(
     _In_ HIMC hIMC)
 {
-    FIXME("stub:(%p)\n", hIMC);
-    return FALSE;
-}
+    TRACE("(%p)\n", hIMC);
 
+    BOOL ret = FALSE;
+    HRESULT hr;
+    IMCLock imcLock(hIMC);
+
+    hr = imcLock.m_hr;
+    if (!imcLock)
+        hr = E_FAIL;
+    if (SUCCEEDED(hr))
+        ret = !!(imcLock.m_pIC->fdwInit & INIT_GUIDMAP);
+
+    return ret;
+}
 
 /***********************************************************************
  *      CtfImeCreateThreadMgr (MSCTFIME.@)
diff --git a/dll/ime/msctfime/msctfime.h b/dll/ime/msctfime/msctfime.h
index 9e492902348..987ccf46d76 100644
--- a/dll/ime/msctfime/msctfime.h
+++ b/dll/ime/msctfime/msctfime.h
@@ -23,6 +23,7 @@
 #include <cicero/cicbase.h>
 #include <cicero/osinfo.h>
 #include <cicero/CModulePath.h>
+#include <cicero/imclock.h>
 
 #include <wine/debug.h>
 
diff --git a/sdk/include/ddk/immdev.h b/sdk/include/ddk/immdev.h
index 5fb513da443..5dfb82f3763 100644
--- a/sdk/include/ddk/immdev.h
+++ b/sdk/include/ddk/immdev.h
@@ -159,6 +159,7 @@ typedef struct INPUTCONTEXTDX
 #define INIT_LOGFONT                    0x00000008
 #define INIT_COMPFORM                   0x00000010
 #define INIT_SOFTKBDPOS                 0x00000020
+#define INIT_GUIDMAP                    0x00000040
 
 // bits for INPUTCONTEXTDX.dwChange
 #define INPUTCONTEXTDX_CHANGE_OPEN          0x1
diff --git a/sdk/include/reactos/cicero/imclock.h b/sdk/include/reactos/cicero/imclock.h
new file mode 100644
index 00000000000..0a2ff2368a8
--- /dev/null
+++ b/sdk/include/reactos/cicero/imclock.h
@@ -0,0 +1,145 @@
+/*
+ * PROJECT:     ReactOS Cicero
+ * LICENSE:     LGPL-2.1-or-later (https://spdx.org/licenses/LGPL-2.1-or-later)
+ * PURPOSE:     Locking and Unlocking IMC and IMCC handles
+ * COPYRIGHT:   Copyright 2023 Katayama Hirofumi MZ <katayama.hirofumi.mz@gmail.com>
+ */
+
+#pragma once
+
+// class _IMCCLock<T_DATA>;
+// class InternalIMCCLock<T_DATA>;
+// class _IMCLock;
+// class IMCLock;
+
+template <typename T_DATA>
+class _IMCCLock
+{
+public:
+    T_DATA *m_pIMCC;
+    HIMCC m_hIMCC;
+    HRESULT m_hr;
+
+    _IMCCLock(HIMCC hIMCC)
+    {
+        m_pIMCC = NULL;
+        m_hr = S_OK;
+        m_hIMCC = hIMCC;
+    }
+};
+
+template <typename T_DATA>
+class InternalIMCCLock : public _IMCCLock<T_DATA>
+{
+public:
+    InternalIMCCLock(HIMCC hIMCC) : _IMCCLock<T_DATA>(hIMCC)
+    {
+        if (hIMCC)
+            _LockIMCC(this->m_hIMCC, &this->m_pIMCC);
+    }
+    ~InternalIMCCLock()
+    {
+        if (this->m_pIMCC)
+            _UnlockIMCC(this->m_hIMCC);
+    }
+    operator T_DATA*() const
+    {
+        return this->m_pIMCC;
+    }
+
+protected:
+    HRESULT _LockIMCC(HIMCC hIMCC, T_DATA **pptr)
+    {
+        if (!hIMCC)
+            return E_INVALIDARG;
+        *pptr = (T_DATA*)::ImmLockIMCC(hIMCC);
+        return (*pptr ? S_OK : E_FAIL);
+    }
+    HRESULT _UnlockIMCC(HIMCC hIMCC)
+    {
+        if (!::ImmUnlockIMCC(hIMCC))
+            return (::GetLastError() ? E_FAIL : S_OK);
+        return S_OK;
+    }
+};
+
+class _IMCLock
+{
+public:
+    LPINPUTCONTEXTDX m_pIC;
+    HIMC m_hIMC;
+    HRESULT m_hr;
+    DWORD m_dw3;
+
+    _IMCLock(HIMC hIMC)
+    {
+        m_pIC = NULL;
+        m_hIMC = hIMC;
+        m_hr = S_OK;
+        m_dw3 = 0;
+    }
+
+    BOOL Invalid() const
+    {
+        return (!m_pIC || m_hr != S_OK);
+    }
+};
+
+class IMCLock : public _IMCLock
+{
+public:
+    IMCLock(HIMC hIMC) : _IMCLock(hIMC)
+    {
+        m_hr = _LockIMC(hIMC, &m_pIC);
+    }
+    ~IMCLock()
+    {
+        if (m_pIC)
+            _UnlockIMC(m_hIMC);
+    }
+
+    void InitContext()
+    {
+        if (!(m_pIC->fdwInit & INIT_COMPFORM))
+            m_pIC->cfCompForm.dwStyle = 0;
+        for (UINT i = 0; i < 4; ++i)
+            m_pIC->cfCandForm[i].dwStyle = 0;
+    }
+
+    BOOL ValidCompositionString()
+    {
+        if (ImmGetIMCCSize(m_pIC->hCompStr) < sizeof(COMPOSITIONSTRING))
+            return FALSE;
+
+        InternalIMCCLock<COMPOSITIONSTRING> imccLock(m_pIC->hCompStr);
+        if (!imccLock)
+            return FALSE;
+
+        return imccLock.m_pIMCC->dwCompStrLen > 0;
+    }
+
+    BOOL UseVerticalCompWindow() const
+    {
+        return m_pIC->cfCompForm.dwStyle && ((m_pIC->lfFont.A.lfEscapement / 900) % 4 == 3);
+    }
+
+    operator INPUTCONTEXTDX*() const
+    {
+        return m_pIC;
+    }
+
+protected:
+    HRESULT _LockIMC(HIMC hIMC, LPINPUTCONTEXTDX *ppIC)
+    {
+        if (!hIMC)
+            return E_INVALIDARG;
+
+        LPINPUTCONTEXTDX pIC = (LPINPUTCONTEXTDX)ImmLockIMC(hIMC);
+        *ppIC = pIC;
+        return (pIC ? S_OK : E_FAIL);
+    }
+    HRESULT _UnlockIMC(HIMC hIMC)
+    {
+        return ::ImmUnlockIMC(hIMC) ? S_OK : E_FAIL;
+    }
+};