diff --git a/include/wx/msw/private.h b/include/wx/msw/private.h
index 4a0b13c8fd..b30c193d5c 100644
--- a/include/wx/msw/private.h
+++ b/include/wx/msw/private.h
@@ -1165,6 +1165,21 @@ inline wxLayoutDirection wxGetEditLayoutDirection(WXHWND hWnd)
                                     : wxLayout_LeftToRight;
 }
 
+// Check if WM_SETTINGCHANGE notifies about the system colours change.
+inline bool wxIsSystemColourChange(LPARAM lParam)
+{
+    // Note that "ImmersiveColorSet" is set both when switching between
+    // light and dark themes and also when changing high contrast mode,
+    // for which an additional message with "WindowsThemeElement" is
+    // also sent, but we don't need to check for it as handling this
+    // one is enough
+    if ( !lParam )
+       return false;
+
+    auto* const what = reinterpret_cast<const TCHAR*>(lParam);
+    return wxStrcmp(what, wxT("ImmersiveColorSet")) == 0;
+}
+
 // ----------------------------------------------------------------------------
 // functions mapping HWND to wxWindow
 // ----------------------------------------------------------------------------
diff --git a/src/msw/window.cpp b/src/msw/window.cpp
index 6c80a6f4c4..531cbe10c2 100644
--- a/src/msw/window.cpp
+++ b/src/msw/window.cpp
@@ -3566,12 +3566,7 @@ wxWindowMSW::MSWHandleMessage(WXLRESULT *result,
         case WM_SETTINGCHANGE:
             // Check for the special case of the message which notifies about
             // the colours change.
-            // Note that "ImmersiveColorSet" is set both when switching between
-            // light and dark themes and also when changing high contrast mode,
-            // for which an additional message with "WindowsThemeElement" is
-            // also sent, but we don't need to check for it as handling this
-            // one is enough
-            if ( lParam && wxStrcmp((TCHAR*)lParam, wxT("ImmersiveColorSet")) == 0 )
+            if ( wxIsSystemColourChange(lParam) )
                 processed = HandleSysColorChange();
             else
                 processed = HandleSettingChange(wParam, lParam);