Tomcat: What is the criteria for the "Thread" column to appear on the Probe Connectors page?

Hello, I would like to know what should be done so that the "Thread" column appears in the "Connectors" screen of the probe, this column usually appears in my Tomcat 6.0 + Probe 2.3.3 installation, but when using the same settings on another machine with Tomcat 6.0 + Probe 2.3.3, this column does not appear.

EDIT: The machine that works, runs Windows with java 1.6.0_18-b07. The machine that does not work, runs Linux with java 1.6.0_18-b07.

Any help will be appreciated, thank you in advance.