How to use rowBGColorCalc

jcompagner:
Web client cant do individual coloring (yet)

Maybe we can improve that in a further version but now we really color the row tag. Then we have to rewrite that
The problem is also then when do you expect to be able to change the colors? All the time? for example when you enter/leave a field? The overhead can be quite large then.

I hoped to replace some unstored calc commonly used for giving a visual feedback for status: e.g. the cell is green if the invoice is payed (or the task has been fixed and so on).

Would this option cause more overhead than a calc? I mean: is an unstored calc returning colored html more efficient than the possible implementation of this feature in rowBgColor?