CCDM: UI.getCurrent().getElement().appendChild does not work in V15

[manolo]

JavaScriptBootstrapUI puts the view in a wrapper appended as a virtualChild.

We might override the getElement() to return the wrapper, it apparently works, but breaks $server methods in client side.
After a further investigation, I saw that the problem is that gwt ServerEventObject class puts the $server method in body (put attention in the initPromiseHandler) whereas calls to this method from server side are bound to the wrapper element (see PublishedServerEventHandlerRpcHandler.invokeMethod).

[joheriks]

Note that this also means that @PreserveOnRefresh is broken for dialogs in V15+. Reloading the page causes open dialogs to be closed.