Any idea to solve this???
We had more or less the same problem. In our column, the icon goes to the next line if the column is not wide enough. Well.. we believe this is due to the structure of the rich:calendar component itself where all the rendered HTML component will reside in a span element, and no css class is available for this span element. So, we ended up creating a wide-enough column to put this calendar.
However, if you are putting it inside a table column... you could probably use some css on that TD element such as noWrap attribute.