R help - May 2009 - why warning appears when set both 'scale' and 'breaks' meanwhile in heatmap.2 of gplots

The warning I met with is attached here:

Warning message:
In heatmap.2(as.matrix(val.sf.ns[-1:-3]), Rowv = F, Colv = T, dendrogram =
"column",  :
  Using scale="row" or scale="column" when breaks
arespecified can produce unpredictable results.Please consider using only one or
the other.


What does 'unpredictable results' mean? Could anyone explain that?
Thanks a lot.

Xin Zheng


	[[alternative HTML version deleted]]