Konsole or Yakuake repeat lines when scrolling

[Guest]

I'm experiencing display problems on Konsole and yakuake.

When I scroll up in the shell, with the wheel or the scroll bar
When I use the up arrow to scroll in a file in vi
When I copy/paste some data in vi
....

I've got the two first lines of the terminal correctly displayed but the third one is repeated until the bottom; giving thinks like that :

drwxr-xr-x 2 intranetdlv users 168 Aug 6 14:55 bin
-rw-r--r-- 1 intranetdlv users 12822 Aug 6 14:55 Test.php
drwxr-xr-x 2 intranetdlv users 656 Aug 6 14:55 math
drwxr-xr-x 2 intranetdlv users 656 Aug 6 14:55 math
drwxr-xr-x 2 intranetdlv users 656 Aug 6 14:55 math
drwxr-xr-x 2 intranetdlv users 656 Aug 6 14:55 math
drwxr-xr-x 2 intranetdlv users 656 Aug 6 14:55 math
drwxr-xr-x 2 intranetdlv users 656 Aug 6 14:55 math
drwxr-xr-x 2 intranetdlv users 656 Aug 6 14:55 math
drwxr-xr-x 2 intranetdlv users 656 Aug 6 14:55 math
drwxr-xr-x 2 intranetdlv users 656 Aug 6 14:55 math
drwxr-xr-x 2 intranetdlv users 656 Aug 6 14:55 math
drwxr-xr-x 2 intranetdlv users 656 Aug 6 14:55 math
drwxr-xr-x 2 intranetdlv users 656 Aug 6 14:55 math
drwxr-xr-x 2 intranetdlv users 656 Aug 6 14:55 math

whatever the file, line, terminal...

Any guess ?