Version: 1.13.0 (using 4.3.95 (KDE 4.3.95 (KDE 4.4 RC2)) "release 214", KDE:KDE4:Factory:Desktop / openSUSE_11.2) Compiler: gcc OS: Linux (x86_64) release 2.6.31.8-0.1-desktop In the message view I press Ctrl+F to search something and it is case sensitive by default. The Settings button next to the search field says that the search is case-insensitive, though. When I toggle it twice it works normally.
Cannot reproduce in KDE 4.4.0