Description of problem: This is a problem which came with KDE4: In konsole profile settings on the "Advanced" tab, there is a checkbox called "Enable flow control using Ctrl+S, Ctrl+Q". This checkbox is disabled so that the feature itself can't be disabled :( Version-Release number of selected component (if applicable): kdebase-4.2.0-2.fc10.x86_64
Looks like an upstream issue, see http://bugs.kde.org/165457