First Programs 'A first program' simplewindow.vala doesn't compile

[stephenmjmaxwell]

The simplewindow code example doesn't compile with error:
valac --pkg gtk+-3.0 simplewindow.vala:6.27-6.32: error: The name Window' does not exist in the context of main' Gtk.Window window = new Window();

It does compile when Gtk.Window window = new Window(); changed to var window = new Gtk.Window ();