The "com.apple.security.pboxd" process is taking 10-20% CPU, and has been for a while now.
From searching around, it seems that this is responsible for showing the "open file" dialog boxes on behalf of sandboxed apps.
It seems odd that it needs 40+ MB of RAM and 20% of my CPU to do this, especially since there don't seem to be any such dialog boxes visible right now.
Is it safe to kill this process?