The VMMouse driver enables support for the special VMMouse protocol
that is provided by VMware virtual machines to give absolute pointer
positioning.

Installing the driver will improve the user experience when using the
mouse to interact with the guest operating system. In particular, use of
the driver improves mouse "lag", provides mouse speed and acceleration
consistent with the user's host operating system, and enables the
auto-grab/ungrab feature in VMware products without requiring the VMware
toolbox application.