When app definitions are tossed around, e.g. new apps created and existing apps removed (e.g. during LD sessions) - there might be exceptions thrown by UI engine claiming that the app layout re-organisation is failing due to the MgnlContext not being set during the operation. The user perceives the issue as broken App Launcher.

This is caused by the fact that the registry update happens outside of the UI thread and we need to take standard measures to "synchronise" that operation with Vaadin lifecycle. We also need to ensure that the context is set (i.e. execute the operation in system context).