Improve handling of WM_SETTINGCHANGE, including forced full repaint

The change is inspired by Patch 2781047 "BugFix for 1632808/2002160 (b144)"
by GrayNM:
Solution, used to detect wallpaper changes, doesn`t work for utilities
like "Wallpaper Master" etc.

Moreover background repainting doesn`t occur even if change was detected

Notes by Kirill:
- 1632808 was closed as fixed long time ago, but was broken by b817683;
- FR 2002160 (aka 2924201) is indeed would be implemented by the patch;

However, the doc on WM_SETTINGCHANGE makes no guarantees about wParam, thus
this is more conservative, but probably more costly fix.

Console/MainFrame.cpp

@@ -783,14 +783,21 @@ LRESULT MainFrame::OnSettingChange(UINT /*uMsg*/, WPARAM /*wParam*/, LPARAM lPar
 
 	wstring strArea(reinterpret_cast<wchar_t*>(lParam));
 
-	if (strArea == L"Windows")
+	// according to WM_SETTINGCHANGE doc:
+	// to change environment, lParam should be "Environment"
+	if (strArea == L"Environment")
 	{
-		g_imageHandler->ReloadDesktopImages();
-		m_activeView->Invalidate();
+		ConsoleHandler::UpdateEnvironmentBlock();
 	}
-	else if (strArea == L"Environment")
+	else
 	{
-		ConsoleHandler::UpdateEnvironmentBlock();
+		// otherwise, we don't know what has changed
+		// technically, we can skip reloading for "Policy" and "intl", but
+		// hopefully they don't happen often, so reload everything
+		g_imageHandler->ReloadDesktopImages();
+
+		// can't use Invalidate because full repaint is in order
+		m_activeView->Repaint(true);
 	}
 
 	return 0;