guest machines in seamless mode should be aware of the host's focus

[Vincent Povirk]

Guest machines in seamless mode are not aware of the host machine's focus. This creates some odd behaviors.

Example one:

• Create a virtual machine in seamless mode.
• Switch to a window in the virtual machine.
• Switch to a window in the host machine.
• The virtual machine's window still has its titlebar highlighted, as if it has focus.

Example two:

• Create a virtual machine in seamless mode.
• Open a menu in the virtual machine.
• Switch to a window in the host machine.
• The virtual machine's menu is still open, even though activating another window would normally close it.

This could probably be solved by creating a hidden "focus is outside the machine" window in the guest and focusing it when the seamless window loses focus in the host.