I will assume you are using the AIR console and not the browser. If this is your first launch of the console since upgrading, close and launch the console. If you have upgraded the appliance to 5.7, make sure you update the AIR console.
Remember that any change you make to the filter will cause it to clear the current content and you will have to wait for one of two things:
1) the correlation of all events in memory (these will be only events received since you logged in, not historic events).
2) new events to arrive after making/editing a filter that match the condition.