A search in Resource Discovery returns over 8,000 results, however when we scroll through the results it is not possible to scroll past the 4000th result.
This behavior is governed by this value in /exlibris/dtl/u3_1/dtle/www_server.conf:
setenv set_result_set_limit 4000
(See page 467 of Digitool Configuration guide)
The value of setenv set_result_set_limit was changed to 10000, and the www server was restarted (start_w at the terminal as dtl user)
After this it was possible to scroll through the entire result set.
The maximum allowed value is 20,000