Mouse cursor invisible when VirtualBox Guest Additions installed

Steps:

• Install ROS in VirtualBox
• Install Guest Additions
• Reboot
• Note: Mouse Integration works as expected
• Disable Mouse Integration (Right Ctrl+I) (so that it is emprisoned within the guest)

Expected: When the VM has captured the mouse, it can't leave the window and the cursor is visible in the VM

Actual: Mouse cursor works as expected when captured, but is invisible

Without Guest Additions installed, cursor is visible just fine.
Tested with r61678.

Important addition for better reproducibility:
When the bug is exposed after rebooting ros, the bug will get "automatically fixed" aka hidden as soon as the mouse pointer changes e.g. to an hourglass for a fraction of a second. This means you will not see it anymore after e.g. opening file-browser via Win+E