FF 4.0 : How to lock result preview to a group instead of a component?

In Filter editor you can lock the preview result to any of the components of the filter just by double clickin over the components and then the preview will be locked to this component and will only show the results of the filter until it reaches this component

Well if you want to do exactly the same with a group you can´t do it, because double clicking over a group will OPEN IT and not lock the preview to it

So I was searching how to do it and finally I found a way that is possible

Instead of double clicking the group you only to have to select the group and then go to the top of the preview and activate the "Lock preview" checkbox