Feature request: Menu to switch among running machines (and host)

[xphileprof]

The menu bar of a running virtual machine displays its name. This could be (optionally) replaced by a menu with an option for each of the various running machines (and possibly one for the host). Choosing an option from this menu could switch the display to the window of the corresponding machine (or to the desktop of the host). When running multiple virtual machines in full-screen mode, this change would make it more convenient to switch among those machines.