Version: (using KDE 4.1.1) OS: Linux Installed from: Ubuntu Packages To reproduce: right-click on the columns header of, for example, the feeds window (Title, Feed, Date...). The "View Columns" popup appear. Now if one tries to add/remove colums (for example Author), not always this works. Mostly of the times they get removed but not added. Moreover sometimes the popup do not disappear after clicking outside; 4-10 clicks (or Esc keystrokes) are necessary to make the popoup disappear. I have found this strange behaviour particularly in the mail and feed sections of kontact. No problems with (for example) konqueror, meaning an application level bug, and not kdelib side.
All those popup issues should be fixed by now. Reopen if not with > 4.2.0