Marco if I understand your comment above correctly then the newest Unity in Vivid resloves this problem.
https://launchpad.net/ubuntu/+source/unity/7.3.1+15.04.20150219.2-0ubuntu1
There are no LIM menus on child windows of Qt apps and the Bug #1312137 was resolved by previous Unity upload in Vivid.
Marco if I understand your comment above correctly then the newest Unity in Vivid resloves this problem.
https:/ /launchpad. net/ubuntu/ +source/ unity/7. 3.1+15. 04.20150219. 2-0ubuntu1
There are no LIM menus on child windows of Qt apps and the Bug #1312137 was resolved by previous Unity upload in Vivid.