Error bars disappear Qtiplot Ubuntu 12.04

Error bars disappear Qtiplot Ubuntu 12.04

I faced this problem while using QtiPlot in Ubuntu 12.04 (WUBI) and could
not find any help on google search. I have created a very nice plot with
QtiPlot which included error bars both for x and y values. The tricky part
comes now: if I save the file as is at this moment and I load it on a
later session it opens as I created, but if I edit the error bar
properties such as the linewidth and color (and save of course) when I
load it on a later session it loads without any errorbar.
Does anybody has faced or knows the solution for this problem?
Regards