A halved container layout edit menu

For some reason only half of menu for “edit container layout” is visible when I select this item from a pop-up list. The other half seems to land to the left of the monitor area, independently on whether it is a laptop monitor or another (second) monitor and independently of the selection of their resolution.
This makes it impossible for me to modify containers structure on the screen and this is why I selected concrete as CMS.
Please help.

AFAIK a fix for the layouts menu will be coming soon in v9.02