I can't reproduce this on Edgy or Feisty, what version of (k)ubuntu are you running?
Also, this may be a duplicate of Bug 58175. -- kate frozen when "Spellcheck Slection" is selected https://launchpad.net/bugs/66890 -- ubuntu-bugs mailing list ubuntu-bugs@lists.ubuntu.com https://lists.ubuntu.com/mailman/listinfo/ubuntu-bugs
