Depending on the icon you are talking about, it could "disappear" because you have hidden it, it has been moved to a folder, it is a bug in theme you are using, or the service book has somehow been deleted.
Since you say you didn't hide it, then maybe it is in a folder, or in a folder and hidden.
Or, if you are using an after-market theme, try switching back to one of the stock themes and test.
Also try resending service books.
As far as labels, give an example. I don't really know the answer, unless it is a bug with the theme you are using.