found the answer:
Until version 2.1, Jetspeed merged portal request parameters with portlet specific
parameters, effectively allowing "shared" parameters.
This is not compliant with the JSR-168 PLT.11, so by default this is now disabled.
By setting merge.portal.parameters.with.portlet.parameters=true this feature can
be "restored".
In the situation of portal and portlet parameters with the same name, by default
the portlet parameters will be provided first in the values array, but this too
can be overridden by setting merge.portal.parameters.before.portlet.parameters=true
Setting both these properties to true will deliver the "old" pre-2.1 behavior.
Note: for individual portlets, these global settings can be overridden by setting these properties as metadata in jetspeed-portlet.xml
merge.portal.parameters.with.portlet.parameters=false
merge.portal.parameters.before.portlet.parameters=false
To use public render parameters from the 2.0 spec