Version: (using KDE 4.3.0)
Installed from: Ubuntu Packages
Selecting "Insert Marker Line" from the menu (or pressing Ctrl+R) does nothing (happens at least in stable KDE 4.3 release packages for Kubuntu 9.04 and also in Kubuntu 9.10 Alpha 4).
This is a known problem (and the main reason it still carries the "alpha"l label) that will be resolved before the 1.2 release.
*** This bug has been marked as a duplicate of bug 192499 ***
Confirmed by two more users here. Alpha 6 of 1.2 (Kubuntu 9.10 alpha 5).