In three instances we have:

appDisplay.js:            this._name.connect('notify::allocation', Lang.bind(this, function (n, alloc) {
appDisplay.js-                let x = this._name.x;
appDisplay.js-                let y = this._name.y;
appDisplay.js-                let width = this._name.width;
appDisplay.js-                let height = this._name.height;
--
genericDisplay.js:        this._list.connect('notify::n-pages', Lang.bind(this, function (grid, alloc) {
genericDisplay.js-            this._updateDisplayControl(true);
genericDisplay.js-        }));
genericDisplay.js:        this._list.connect('notify::page', Lang.bind(this, function (grid, alloc) {
genericDisplay.js-            this._updateDisplayControl(false);
genericDisplay.js-        }));

The second parameter of a notify:: signal is actually a 'param spec' - an object with information about the property.It's not the allocation for notify::allocation. It's definitely not the allocation for notify::n-pages. In all cases above we can just ignore both parameters and use 'function() {...}' as we do elsewhere in the code.