I am using VBO module to create 2 pages one for controlling the nodes and another for controlling the users..
I used the magic tabs (I also tried quick tabs module) to wrap each page in a tab.
the first time i load the page, the context menu works well but once I click on the second tab (ajax mode) the context menu does not get invoked.

Looking at the code, it seems that the pre_render function is not overriding the default values.