LRESULT MyApp::WindowProc(UINT message, WPARAM wParam, LPARAM lParam)
{
	switch(message) {
		case WM_SYSCOLORCHANGE:
		case WM_THEMECHANGED:
			PostCallback(THISBACK(HandleChanges));
			return FALSE;
	}
	return TopWindow::WindowProc(message, wParam, lParam);
}
...

void MyApp::HandleChanges()
{
    RefreshMyAppStyle(); // call custom chameleon style implementation
    RefreshLayoutDeep(); // update GUI look
}