Did you go to the 3Dconnexion web site and download/install the new driver that is compatible with Mavericks?
I had to do that to get my SpaceNavigator to work again after the Mavericks upgrade...and all buttons/etc work fine...
One of the forum moderators
AC 28 USA and earlier • macOS Sequoia 15.2, MacBook Pro M2 Max 12CPU/30GPU cores, 32GB