In richfaces-references it says in the property-definitions:
renderRegionOnly: Default value is "false".
but at another place in the manual it says:
The processing could be also accelerated if a region decoded for the processing passes straight
away into Encode. But to update some data out of the region or on another region, use the
"renderRegionOnly" attribute set to "false" ("true" on default) to change this behaviour.
("true" on default)or
Default value is "false".
Okay, now it s clear.
The log says me, that the false is the default for renderRegionOnly.