Hi! Thanks for looking into this, there are less and less developers bothering to make things work with Unity 3.5.7
I made empty project with only new version of NGUI, i opened one of the example scenes just to make sure I am not missing something. I click on the widget in the scene and right click (when released) gives me greyed out menu.
I am using MacOS though, just to let you know. Good to hear that it's working on your system with Unity 3.5.7, then it is possible to make it work on my system to.
Great update. Thanks!