Editor that warns when file on disk changes

Is there any simple editor for KDE 3.3.2 (level "a") that, like EMACS, warns users if a file that they are trying to edit has been changed on disk since it was loaded? I tried kwrite 4.3 and kate 2.3.2, and in both, even when saving to a file that has been changed on disk there is no prior warning. Yes, I did enable the option "Warn about files modified by foreign processes" in kate. OS is SuSE 9.2. -- Felix E. Klee