I installed VITO Button Mapper on my X50 since I wanted to assign different actions to the buttons inside different programs.
The problem is that after I installed (and activated) Button Mapper the ordinary functionality of buttons disapered. I.e. Within Calendar pressing caldendar would switch between the views, pressing contacts within Contacts switching category.
The problem occurs as soon I've activated Button Mapper, i.e. havn't done any configuration of the buttons yet.
That's becouse, VITO Button Mapper has it's own settings, which are not set up by default. If you uninstall it, you would have original settings. As for Button Mapper, you just have to set it up as you wish.