Version: 1.5.5 (using KDE 3.5.4 "release 88.1" , openSUSE ) Compiler: Target: x86_64-suse-linux OS: Linux (x86_64) release 2.6.16.13-4-default First create some classes at the logical view and then associate or generalise them. Save and exit. Reenter umbrello and the relations are gone.
This happens on intermediate versions from KDE SVN (r575645 to r585671). Please use the official release which is coming out today with KDE 3.5.5.