Spotted by Marcus Meissner.

Forks with ifval == FALSE do not count as "parallel", so nested forks are
still allowed. Please note that calling _vcomp_fork(FALSE, ...) or directly
calling the callback is still different in some aspects, the synchronization
functions run in a different context for example.

In Win32, minimized windows are generally not considered maximized,
but restoring a minimized window that had been maximized returns it to
the maximized state.

In X11, at least with some window managers (I tested metacity and
gnome shell), the maximized state is meaningful for minimized windows.
If we remove the net_wm maximized state from windows we minimize, they
will still be unmaximized when the WM restores them.