When ISBoxer 40 comes out, it includes features to improve Video FX-based Window Layouts... such as the ability to click (or use some hotkey) to switch to the one you're over.
Until then unfortunately you would build this using a
Click Bar behind the Video FX.
To build this you will need one
Mapped Key (you can put it in an existing Key Map, like Always On), with a
Window Focus Action in it. You don't need to do anything special to this Mapped Key, it doesn't need multiple Steps, you don't need a Hotkey on it, the ONLY things you need to do after it is created are give it a relevant name ("activate window plz") and add a Window Focus Action. The Window Focus Action should have its button set to "Selected Filter Target" and then set the Filter Target to "Window:Current". That way, in order to focus a specific window, you can tell it to do this Mapped Key. That will link up directly to a Click Bar.
When you've got your Mapped Key, it's time to build the Click Bar. The instructions on the Click Bar page should get you started, but the idea is that you set up a big fat button right behind the Video FX view of some window, and have the Click Bar send our new Mapped Key to that window.
The linked pages should have all of the other information you need, but let me know if you get stuck on something. If you're new to ISBoxer and not intending to spend some time learning wtf I just said to do, then this might be a little much -- you can also just wait for ISBoxer 40.