[R] Sorting problem

[Paul JH Drake]

Hi
I'm using R 2.0 in SuSE 9.2.

When I plot data as a boxplot, the boxes appear on the plot in
alphabetical order (of group) rather than the order in which they appear
in the data. So far, the only thing I can do to fix this is to prefix
the group labels with a,b,c...etc to trick R into plotting them in the
right order.

Can sorting be turned off?
How should I address this sensibly?

Thanks in advance

Paul