I have noticed that when elements are hide on the screen some are still click able. This happened to me couple times, on the Apartments when you click on the M button you can still click on - and + buttons even tough they are hidden.
Another occasion this happened was I had my R&D on north of a city when I tried to click on some of the elements on the menu (select a product for R&D)the click applied to the building behind the window.
Hope this helps. Thanks
