Version: 1.5.6 (using KDE KDE 3.5.6) Installed from: Ubuntu Packages 1. The classes cannot be deleted from the tree by pressing the DEL key. A context popup (right click on the class) must be used. Weird, because the classes CAN be deleted from the workspace (= edited diagram) by pressing DEL 2. After deletion, some classes with random names appear. If you delete them, a new ones appear 3. After saving a sequence diagram, the operation names changed into random ones (that's particularly obscure!) I can provide a screenshot, but I dunno how to upload it here.
fixed in 1.5.71 *** This bug has been marked as a duplicate of 145709 ***