Customize Chart needs love before release

[Adrian Custer <acuster gnome org>]

hey all,

playing around with charting, trying to see what is new.

Double click on a chart ==> Customize chart appears

In the top right part of the dialog is a preview which helpfully lets us
mess around with the pieces. However, it has not been even slightly bug
proofed. I've now got it to display nothing (all grey) despite having
two charts in there. One is off screen (unrecoverably); the other is
inverted inside out and therefore apparently not drawn. Before you
enable this functionality *please* have at it a bit to make sure users
don't lose their charts.

--adrian