"Other" elements in Mastering Chemistry

A number of people have run into the problem of entering elements other than those listed in the pop-down menu when drawing Lewis structures in Mastering Chemistry. If you need an unlisted element (like, perhaps, Si...), you can draw a carbon (or any other element) then double click on the "C". At that point, you should be able to type in the symbol of whatever element you need. This actually works for any element, so if you want to draw your entire skeleton structure in using the default element (carbon) and then double click your way through to change elements to O or F or whatever else, you can do that.