Black square bug

We has a several bug's reports describes as a "Black square" in the place where was mouse pointer before hide. We discovered this bug found it appears on some computers, never on others and always under virtual machine (VMWare, Virtual Box with Guest add-on installed).
It is incompatibility with  some video card or video card drivers.

To fix this bug, go to "Control Panel", Open "Mouse" applet, activate "Pointers" tab. Clear "Enable pointer shadow" checkbox to turn off shadow. Press Ok or Apply button. No Black square anymore.

Control panel mouse enable/disable pointer shadow
Mouse pointer shadow in Windows XP. Clear it to fix Black square bug.
See also Google Chrome browser black square bug

Download Cursor Hider to test your system for black square bug.