Tomcat memery leak with drools 4.0.7 or 5.0.1

The memory is never released !!! (never ever ) when à Stop and Start or restart Tomcat.

A made this test with a simple Drools call with a simple webapp and i tried with 4.0.7 and 5.0.1 drools version. The problem is the same.
We need to stop tomcat process to release memory. Until this stop each Tomcat "Restart" with a drools call, will never release the memory.
I made graphic with VisualWM, and we can see this problem !
I made a zip of my simple Eclipse project (webapp + drools) and word file for more information and screen copy of VisualVM.
Thanks for help.
Emmanuel GREFFET ( FRANCE)