pie-charts colors update

[remy <remy.cazabet AT gmail.com>]

Hi,
I try to use pie-charts to represent my nodes, but I need to change their
colors dynamically. 
I'm using 
n.setAttribute("ui.style", "shape:pie-chart;fill-color:XXX").

It works well the first time, but if I do it again with new colors, it keeps
the old ones. It seems to be an actualization problem, because if I first
change the shape to a cross for example, then I can correctly set the colors
for the pie-chart anew. (But only if the cross is displayed. If I change to a
cross, them come back to a pie-chart without graphic update, it keeps the old
colors.)

To give a concrete example of the problem, if I write 

n.setAttribute("ui.style", "shape:pie-chart;fill-color:red");

Thread.sleep(1000);
n.setAttribute("ui.style", "shape:pie-chart;fill-color:blue");

the node stays red.

Do you have a solution ? Thanks