Issue has been fixed - or at least workaround - by the QlikTech support.
On the Windows Desktop:
- Right click - screen resolution, click on "Make text and other items larger or smaller".
By default, the zoom on my laptop was 125%. Switched back to 100% the issue disapears in QlikView 11.
It is still a bug related to QV11 since the issue was not there on QV10 but at least this workaround allows working...
Hope this might help other people before the QlikTech dev team can solve the bug.