I am a web developer and I have for a long time been running ubuntu in VirtualBox with two screens without any problems. Today after upgrade to 17.10 this does not work anymore. The mouse behaves very strange as only a few of all GUI elements in the desktop reacts to the mouse clicks. I can for example not click the system menu (with power off, Wifi, etc) in the upper right corner and most (but not all) of the applications in the application bar can not be clicked. Nothing happens when you click. If I start Virtual Box with one screen everything works perfectly. Very annoying! I have tried to upgrade VirtualBox and Guest Additions and different screen combinations but nothing works.