@Override
    public void onBrowserEvent(Event event) {
        int type = DOM.eventGetType(event);
        if ((type & Event.KEYEVENTS) != 0) {
            // Fire the keyboard event. Hang on to the current event object so that
            // cancelKey() and setKey() can be implemented.
            currentEvent = event;
            // Call the superclass' onBrowserEvent as that includes the key event
            // handlers.
            super.onBrowserEvent(event);
            currentEvent = null;
        } else {
            // Handles Focus and Click events.
            super.onBrowserEvent(event);
        }
    }
Determines whether or not the widget is read-only.

@return <code>true</code> if the widget is currently read-only,
<code>false</code> if the widget is currently editable
stroom-core-client-widget/src/main/java/com/google/gwt/user/client/ui/ValueBoxBase.java