Is there any way to cancel or abort a running Store Read call running over a PageProxy?
I saw that other proxies got an "abort()" function, but the functions is empty for PageProxy.

We got the problem that closing a Ext.Portal before the Store Read call finishes leads to an clientside exception. Currently we wait for the store read calls to finish and close the Portal afterwards. But sometimes they can take some time and would be better to cancel them and close the tabs directly.