Fix#2257. Fix#2929. Fix#2935 (probably in a way that will not satisfy the requester). 2257 and 2929 requested changes that ultimately affect the same section of code, so it's appropriate to deal with them together. 2257 requests the ability to make the chart background transparent (so that the Excel gridlines are visible beneath the chart), and the ability to hide an Axis. 2929 requests the ability to set a gradient background on the chart.
oleibman