diff --git a/reactos/dll/cpl/desk/appearance.h b/reactos/dll/cpl/desk/appearance.h
index 7bbdb264f27..9f56ad3bedc 100644
--- a/reactos/dll/cpl/desk/appearance.h
+++ b/reactos/dll/cpl/desk/appearance.h
@@ -147,6 +147,7 @@ VOID ApplyScheme(PCOLOR_SCHEME scheme, PTHEME_SELECTION pSelectedTheme);
 BOOL ActivateTheme(PTHEME_SELECTION pSelectedTheme);
 void CleanupThemes(IN PTHEME pThemeList);
 BOOL DrawThemePreview(HDC hdcMem, PCOLOR_SCHEME scheme, PTHEME_SELECTION pSelectedTheme, PRECT prcWindow);
+BOOL ActivateThemeFile(LPCWSTR pwszFile);
 
 /* prototypes for appearance.c */
 INT_PTR CALLBACK AppearancePageProc(HWND hwndDlg, UINT uMsg, WPARAM wParam, LPARAM lParam);
diff --git a/reactos/dll/cpl/desk/desk.c b/reactos/dll/cpl/desk/desk.c
index 3bb931e0255..fa59d1733d3 100644
--- a/reactos/dll/cpl/desk/desk.c
+++ b/reactos/dll/cpl/desk/desk.c
@@ -124,7 +124,7 @@ DisplayApplet(HWND hwnd, UINT uMsg, LPARAM wParam, LPARAM lParam)
 {
     HPROPSHEETPAGE hpsp[MAX_DESK_PAGES];
     PROPSHEETHEADER psh;
-    HPSXA hpsxa;
+    HPSXA hpsxa = NULL;
     TCHAR Caption[1024];
     UINT i;
     LPWSTR *argv = NULL;
@@ -140,36 +140,38 @@ DisplayApplet(HWND hwnd, UINT uMsg, LPARAM wParam, LPARAM lParam)
     {
         int argc;
         int i;
-        LPCWSTR pszCommandLine = (LPCWSTR)lParam;
 
-        argv = CommandLineToArgvW(pszCommandLine, &argc);
+#if 0
+        argv = CommandLineToArgvW((LPCWSTR)lParam, &argc);
+#else
+        argv = CommandLineToArgvW(GetCommandLineW(), &argc);
+#endif
 
         if (argv && argc)
         {
             for (i = 0; i<argc; i++)
             {
+#if 0
                 if (argv[i][0] == L'@')
                     pwszSelectedTab = &argv[i][1];
+#else
+                if (wcsncmp(argv[i], L"desk,@", 6) == 0)
+                    pwszSelectedTab = &argv[i][6];
+#endif
                 else if (wcsncmp(argv[i], L"/Action:", 8) == 0)
                     pwszAction = &argv[i][8];
                 else if (wcsncmp(argv[i], L"/file:", 6) == 0)
                     pwszFile = &argv[i][6];
             }
         }
-
-        /* HACK: shell32 doesn't give the correct params to CPL_STARTWPARMSW so we need to ... improvise */
-        if (wcsncmp(pszCommandLine, L"/file:", 6) == 0)
-        {
-            LPCWSTR pwszType = wcsrchr(pszCommandLine, L'.');
-            if (pwszType && wcsicmp(pwszType, L".msstyles") == 0)
-            {
-                pwszFile = &pszCommandLine[6];
-                pwszSelectedTab = L"Appearance";
-                pwszAction = L"OpenMSTheme";
-            }
-        }
     }
 
+    if(pwszAction && wcsncmp(pwszAction, L"ActivateMSTheme", 15) == 0)
+    {
+        ActivateThemeFile(pwszFile);
+        goto cleanup;
+    }
+    
     g_GlobalData.pwszFile = pwszFile;
     g_GlobalData.pwszAction = pwszAction;
     g_GlobalData.desktop_color = GetSysColor(COLOR_DESKTOP);
@@ -212,6 +214,7 @@ DisplayApplet(HWND hwnd, UINT uMsg, LPARAM wParam, LPARAM lParam)
 
     PropertySheet(&psh);
 
+cleanup:
     if (hpsxa != NULL)
         SHDestroyPropSheetExtArray(hpsxa);
 
diff --git a/reactos/dll/cpl/desk/theme.c b/reactos/dll/cpl/desk/theme.c
index e541d064772..858033c42ac 100644
--- a/reactos/dll/cpl/desk/theme.c
+++ b/reactos/dll/cpl/desk/theme.c
@@ -1010,3 +1010,51 @@ DrawThemePreview(IN HDC hdcMem, IN PCOLOR_SCHEME scheme, IN PTHEME_SELECTION pSe
 
     return SUCCEEDED(hres);
 }
+
+BOOL ActivateThemeFile(LPCWSTR pwszFile)
+{
+    PTHEME pThemes;
+    THEME_SELECTION selection;
+    COLOR_SCHEME scheme;
+    BOOL ret = FALSE;
+
+    pThemes = LoadThemes();
+    if (!pThemes)
+        return FALSE;
+
+    LoadCurrentScheme(&scheme);
+
+    if (pwszFile)
+    {
+        ret = FindOrAppendTheme(pThemes, pwszFile, NULL, NULL, &selection);
+        if (!ret)
+            goto cleanup;
+
+        ret = LoadSchemeFromTheme(&scheme, &selection);
+        if (!ret)
+            goto cleanup;
+    }
+    else
+    {
+        ret = GetActiveClassicTheme(pThemes, &selection);
+        if (!ret)
+            goto cleanup;
+
+        ret = LoadSchemeFromReg(&scheme, &selection);
+        if (!ret)
+            goto cleanup;
+    }
+
+    ret = ActivateTheme(&selection);
+    if (!ret)
+        goto cleanup;
+
+    ApplyScheme(&scheme, &selection);
+
+    ret = TRUE;
+
+cleanup:
+    CleanupThemes(pThemes);
+
+    return ret;
+}