Windows autoraise after fast mouse movements

[AlainKnaff]

When moving the mouse quickly from one window to another, occasionally random windows which are traversed on the path autoraise. This didn't happen before the last apt-get upgrade

Can be reproduced by jiggling the mouse between 2 windows where one partly covers the other. After much jjiggling the background window raises in front.

1) > lsb_release -rd
Description: Ubuntu 14.04.4 LTS
Release: 14.04
2) > apt-cache policy kde-window-manager
kde-window-manager:
  Installed: 4:4.11.11-0ubuntu0.2
  Candidate: 4:4.11.11-0ubuntu0.2
  Version table:
 *** 4:4.11.11-0ubuntu0.2 0
        500 http://be.archive.ubuntu.com/ubuntu/ trusty-updates/universe amd64 Packages
        500 http://security.ubuntu.com/ubuntu/ trusty-security/universe amd64 Packages
        100 /var/lib/dpkg/status
     4:4.11.8-0ubuntu6 0
        500 http://be.archive.ubuntu.com/ubuntu/ trusty/universe amd64 Packages
3) What I expected to happen
Windows should stay put, except when asked
4) What happened instead
Windows randomly autoraise