2.27. Support for Keyboard Indicator Synchronization

This feature makes the host keyboard indicators (LEDs) match those of the VM's emulated keyboard when the machine window is active. It is currently implemented for Mac OS X and Windows hosts. This feature is enabled by default on supported host OSes. You can disable this feature by running the following command:

VBoxManage setextradata "VM name" GUI/HidLedsSync 0

This is a per-VM setting, which is enabled by default.