diff --git a/sdk/include/reactos/imm32_undoc.h b/sdk/include/reactos/imm32_undoc.h
index 3d7296bd272..0b5228d46b2 100644
--- a/sdk/include/reactos/imm32_undoc.h
+++ b/sdk/include/reactos/imm32_undoc.h
@@ -261,6 +261,22 @@ BOOL WINAPI ImmSetActiveContextConsoleIME(_In_ HWND hwnd, _In_ BOOL fFlag);
 BOOL WINAPI ImmActivateLayout(_In_ HKL hKL);
 BOOL WINAPI ImmFreeLayout(_In_ HKL hKL);
 
+BOOL WINAPI
+ImmGetHotKey(
+    _In_ DWORD dwHotKey,
+    _Out_ LPUINT lpuModifiers,
+    _Out_ LPUINT lpuVKey,
+    _Out_opt_ LPHKL lphKL);
+
+BOOL WINAPI
+ImmSetHotKey(
+    _In_ DWORD dwID,
+    _In_ UINT uModifiers,
+    _In_ UINT uVirtualKey,
+    _In_opt_ _When_((dwAction == SETIMEHOTKEY_ADD) &&
+                    !(IME_HOTKEY_DSWITCH_FIRST <= dwHotKeyId &&
+                      dwHotKeyId <= IME_HOTKEY_DSWITCH_LAST), _Null_) HKL hKL);
+
 BOOL WINAPI
 ImmWINNLSEnableIME(
     _In_opt_ HWND hWnd,
diff --git a/sdk/include/reactos/undocuser.h b/sdk/include/reactos/undocuser.h
index 0f974c8fedf..f944f92acc1 100644
--- a/sdk/include/reactos/undocuser.h
+++ b/sdk/include/reactos/undocuser.h
@@ -202,7 +202,16 @@ LONG WINAPI CsrBroadcastSystemMessageExW(DWORD dwflags,
                                          WPARAM wParam,
                                          LPARAM lParam,
                                          PBSMINFO pBSMInfo);
-BOOL WINAPI CliImmSetHotKey(DWORD dwID, UINT uModifiers, UINT uVirtualKey, HKL hKl);
+
+BOOL WINAPI
+CliImmSetHotKey(
+    _In_ DWORD dwID,
+    _In_ UINT uModifiers,
+    _In_ UINT uVirtualKey,
+    _In_opt_ _When_((dwAction == SETIMEHOTKEY_ADD) &&
+                    !(IME_HOTKEY_DSWITCH_FIRST <= dwHotKeyId &&
+                      dwHotKeyId <= IME_HOTKEY_DSWITCH_LAST), _Null_) HKL hKL);
+
 HWND WINAPI SetTaskmanWindow(HWND);
 HWND WINAPI GetTaskmanWindow(VOID);
 HWND WINAPI GetProgmanWindow(VOID);
diff --git a/win32ss/include/ntuser.h b/win32ss/include/ntuser.h
index d477cfd2808..9a63c4a5ac8 100644
--- a/win32ss/include/ntuser.h
+++ b/win32ss/include/ntuser.h
@@ -2327,7 +2327,7 @@ NtUserGetImeHotKey(
     _In_ DWORD dwHotKeyId,
     _Out_ PUINT lpuModifiers,
     _Out_ PUINT lpuVirtualKey,
-    _Out_ LPHKL lphKL);
+    _Out_opt_ LPHKL lphKL);
 
 BOOL
 NTAPI
@@ -3138,7 +3138,7 @@ NtUserSetImeHotKey(
     _In_ DWORD dwHotKeyId,
     _In_ UINT uModifiers,
     _In_ UINT uVirtualKey,
-    _In_ HKL hKL,
+    _In_opt_ HKL hKL,
     _In_ DWORD dwAction);
 
 BOOL
diff --git a/win32ss/user/imm32/keymsg.c b/win32ss/user/imm32/keymsg.c
index 304fd5b3815..d608843769a 100644
--- a/win32ss/user/imm32/keymsg.c
+++ b/win32ss/user/imm32/keymsg.c
@@ -649,7 +649,7 @@ ImmGetHotKey(
     _In_ DWORD dwHotKey,
     _Out_ LPUINT lpuModifiers,
     _Out_ LPUINT lpuVKey,
-    _Out_ LPHKL lphKL)
+    _Out_opt_ LPHKL lphKL)
 {
     TRACE("(0x%lX, %p, %p, %p)\n", dwHotKey, lpuModifiers, lpuVKey, lphKL);
     if (lpuModifiers && lpuVKey)
diff --git a/win32ss/user/ntuser/ime.c b/win32ss/user/ntuser/ime.c
index d897c67369c..6f8ff81a4d9 100644
--- a/win32ss/user/ntuser/ime.c
+++ b/win32ss/user/ntuser/ime.c
@@ -363,7 +363,7 @@ IntSetImeHotKey(
     _In_ DWORD dwHotKeyId,
     _In_ UINT uModifiers,
     _In_ UINT uVirtualKey,
-    _In_ HKL hKL,
+    _In_opt_ HKL hKL,
     _In_ DWORD dwAction)
 {
     PIMEHOTKEY pNode;
@@ -435,7 +435,7 @@ NtUserGetImeHotKey(
     _In_ DWORD dwHotKeyId,
     _Out_ PUINT lpuModifiers,
     _Out_ PUINT lpuVirtualKey,
-    _Out_ LPHKL lphKL)
+    _Out_opt_ LPHKL lphKL)
 {
     PIMEHOTKEY pNode = NULL;
 
@@ -484,7 +484,7 @@ NtUserSetImeHotKey(
     _In_ DWORD dwHotKeyId,
     _In_ UINT uModifiers,
     _In_ UINT uVirtualKey,
-    _In_ HKL hKL,
+    _In_opt_ HKL hKL,
     _In_ DWORD dwAction)
 {
     BOOL ret;
diff --git a/win32ss/user/user32/windows/input.c b/win32ss/user/user32/windows/input.c
index 988254d2fae..db8229dc88e 100644
--- a/win32ss/user/user32/windows/input.c
+++ b/win32ss/user/user32/windows/input.c
@@ -66,7 +66,6 @@ IMEHOTKEYENTRY DefaultHotKeyTableC[] =
 #define FE_KOREAN               (1 << 3)
 
 // Sets the far-east flags
-// Win: SetFeKeyboardFlags
 VOID FASTCALL IntSetFeKeyboardFlags(LANGID LangID, PBYTE pbFlags)
 {
     switch (LangID)
@@ -143,8 +142,6 @@ Failure:
     return FALSE;
 }
 
-
-/* Win: LoadPreloadKeyboardLayouts */
 VOID IntLoadPreloadKeyboardLayouts(VOID)
 {
     UINT nNumber, uFlags;
@@ -258,11 +255,18 @@ CliSaveImeHotKey(DWORD dwID, UINT uModifiers, UINT uVirtualKey, HKL hKL, BOOL bD
     return ret;
 }
 
-/*
+/**
  * @implemented
- * Same as imm32!ImmSetHotKey.
+ * @note Same as imm32!ImmSetHotKey.
  */
-BOOL WINAPI CliImmSetHotKey(DWORD dwID, UINT uModifiers, UINT uVirtualKey, HKL hKL)
+BOOL WINAPI
+CliImmSetHotKey(
+    _In_ DWORD dwID,
+    _In_ UINT uModifiers,
+    _In_ UINT uVirtualKey,
+    _In_opt_ _When_((dwAction == SETIMEHOTKEY_ADD) &&
+                    !(IME_HOTKEY_DSWITCH_FIRST <= dwHotKeyId &&
+                      dwHotKeyId <= IME_HOTKEY_DSWITCH_LAST), _Null_) HKL hKL)
 {
     BOOL ret;