:-( Bug confirmed for me using Trusty, with VirtualBox Version 4.3.36 on 4.4.0-143-generic, reverting back to 4.4.0-142-generic resolved issue also.
:-(
Bug confirmed for me using Trusty, with VirtualBox Version 4.3.36 on 4.4.0-143-generic,
reverting back to 4.4.0-142-generic resolved issue also.