User library fileset cannot be modified

STEP: prepare two library filesets, lets say myLib1, myLib2 via preferences (Java -> Build Path -> User Libraries)
STEP: create project with archives support
STEP: create some archive in the project
STEP: add new user library fileset in the archive (myLib1)
STEP: select myLib1 in archives explorer, invoke its context menu and select Edit fileset
STEP: in "User Library Fileset Wizard" dialog select myLib2, confirm it
FAIL: there is still myLib in archives explorer, not myLib2 as it should be