I finaly found the solution. Don't know if it's a bug, but...
At least for kde, go to the control panel, application appearance (I translate from french), GNOME/GTK application style, and for GTK2 choose... the default (Clearlooks). That is press the "default" in the bottom of the panel.
For whatever reason, the openSUSE install setup is not the kde default (including in openSUSE-branding), but the BreezyGTK that gives the odd result.
Many other setups are also suboptimal, but Clearlooks works perfectly.