Well, the only thing I can find is in Settings\User Preferences\Printing tab where you can force printed objects to black and white... The odd thing though is the other objects are printing in color, so I do not believe that is the issue here, but I cannot find any chart setting that drops the color, but maybe the hatch pattern is such that it appears as grey, but the odd thing there is I cannot even select the option to not use color. Any chance you can attach a sample app that shows the same, so I can dig around and try to find what is causing it? I would think it has to be in the Chart Properies Color tab settings though, only thing that makes sense here.
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