reports - tickets - for openned tickets

Hi,

I have a question about the report.
In the Report -> tickets -> for openned tickets - monthly/yearly/global..
For the 'responsible', it doesn't show the pie chart, but shows the error message:

ERROR : Undefined offset: 8
in pChart.class
at line 2697

It seems like the responsible > 8 will cause the error.

I tried to choose one with project with 8 responsibles, the pie chart displays normally but the legend list only shows 7 responsibles (it seems the 8th is cut).
Please help to check.

Thanks a lot.

Best Regards,
Selina