Version Management - compare

Hi,

I use BO 4.0 SP6 and few days ago I started to use Version Management.

Everything works fine but in History is the button - Compare.

In my opinion it should use to compare two checked version of reports. But in my situation after choosed two reports this button is inactive - I can't push it. Other buttons work fine.

And one additional question - all information which I see in hisotry (data, user, etc) are collected in Audit database?

Regards