OUYA - how to right click (and delete source)

Hi, Just got my OUYA and have installed 12.2 Frodo for Android on it.

I mistakenly setup a Video source and now want to remove it (or at least edit it).

However, I am unable to "right click" to bring up the context menu via the controller. So i plugged in a USB mouse (which works fine) and tried right-clicking - this doesn't work either.

I tried holding the left mouse button down for a few seconds, but this just opened the folder eventually.

How do I get to the "settings" or be able to "delete" a video source?

(and why doesn't the left hand menu have these context menu items or some of the basic items?)

Hope you can help,
Thanks
Juzzybear