Same story here (WAS 126.96.36.199/AIX 5.3). User picker didn't work in CSX 1.3, worked from 1.4.0-1.5.0, not working again with 1.6.0. Also, the scenarios for status levels don't show up (but did show up in 1.5.0).
cmacha: what OS/JDK/version of WAS are you running?
Can you try updating WAS to 188.8.131.52? There's an acknowledged bug in WAS where they incorrectly interpret the servlet path. Fixes and description here: