See the section "Mouse Cursor Overwritten" at https://wiki.archlinux.org/index.php/Steam for a solution that can easily be extended to KDE.
Thanks, executing commands bellow worked:
cd /usr/share/icons/Oxygen_White/cursors/
sudo su
ln -s ./left_ptr ./arrow
ln -s ./size_fdiag ./bottom_right_corner
ln -s ./size_fdiag ./top_left_corner
ln -s ./size_bdiag ./bottom_left_corner
ln -s ./size_bdiag ./top_right_corner
ln -s ./size_hor ./left_side
ln -s ./size_hor ./right_side
ln -s ./size_ver ./top_side
ln -s ./size_ver ./bottom_side
exit
This is a duplicate of issue #2
Also happens on openSUSE 12.2 with KDE 4.9.4 and it seems to always fall back on the left-handed version of the pixelish XServer cursor which makes this even more weird.
As a workaround on Kubuntu, you can install the dmz-cursor-theme package (used in the Unity version of Ubuntu) and switch to the DMZ cursor theme in system settings.
Not sure if the Oxygen cursor theme should be provided with the symlinks out of the box.
Filed as an Ubuntu bug:
https://bugs.launchpad.net/ubuntu/+source/oxygencursors/+bug/1094140
I don't think that this is a bug in KDE/Kubuntu or whatever. Steam should just use the system mouse cursor graphics theme.
Agreed, Steam shouldn't frivolously change the system theme.
However, I believe that having the cursors Steam uses missing from the Oxygen theme is a bug.
Never use "sudo su", the better way to do it is "sudo -s"- one command instead of two.
Nothing extracted yet.
When mouse cursor is in steam window it uses generic xserver cursor theme instead of nice KDE cursor theme. KDE 4.10 beta2, Kubuntu 12.10.