UIProvider provider = null;
Class<? extends UI> uiClass = null;
for (UIProvider p : uiProviders) {
// Check for existing LegacyWindow
if (p instanceof LegacyApplicationUIProvider) {
LegacyApplicationUIProvider legacyProvider = (LegacyApplicationUIProvider) p;
UI existingUi = legacyProvider
.getExistingUI(classSelectionEvent);
if (existingUi != null) {
reinitUI(existingUi, request);
return existingUi;
}