switch to parent window after closing child window

as gladly donated by @basaran
see https://github.com/lcpz/awesome-copycats/issues/301

rc.lua.template

@@ -811,4 +811,21 @@ end)
 client.connect_signal("focus", function(c) c.border_color = beautiful.border_focus end)
 client.connect_signal("unfocus", function(c) c.border_color = beautiful.border_normal end)
 
+-- switch to parent after closing child window
+local function backham()
+    local s = awful.screen.focused()
+    local c = awful.client.focus.history.get(s, 0)
+    if c then
+        client.focus = c
+        c:raise()
+    end
+end
+
+-- attach to minimized state
+client.connect_signal("property::minimized", backham)
+-- attach to closed state
+client.connect_signal("unmanage", backham)
+-- ensure there is always a selected client during tag switching or logins
+tag.connect_signal("property::selected", backham)
+
 -- }}}