boolean canUndo = undoManager.canUndo();
boolean canRedo = undoManager.canRedo();
if (model.canUndo() != canUndo || model.canRedo() != canRedo) {
model.canUndo = canUndo;
model.canRedo = canRedo;
UndoRedoStateChangedEvent event =
new UndoRedoStateChangedEventImpl(model, Json.createObject().set("canUndo", canUndo)
.set("canRedo", canRedo));
store.getBus().publishLocal(Constants.Topic.STORE + "/" + id + "/" + EventType.UNDO_REDO_STATE_CHANGED,
event);
}