Currently we only connect to the 'notify::n-workspaces' signal the
first time the overview is shown, which means we will miss any
changes to the workspace layout in the meanwhile.
In particular, the decision of whether the workspace switcher should be
shown is taken before the dynamic workspace handling takes over, and is
thus based entirely on the value of the num-workspaces user preference
rather than the actual number of workspaces.
Just connect the signal in _init() (with the nice side-effect to make it
explicit that the signal handler won't ever be disconnected).
https://bugzilla.gnome.org/show_bug.cgi?id=673198
76005f5adf