Avoid resetting [at least some] percentile chart properties when timeline chart changes

[giltene]

When editing chart properties to control text (e.g. title for the chart and each axis), a currently cumbersome situation exists where any change to the top (timeline) chart replots and resets all the options for the bottom (percentile) chart. While some changes (e.g. to ranges) and the actual replot is needed, the resetting of the text properties is not, and causes a lot of extra manual work.

Please change to avoid resetting the text fields (chart title and axes text) in the percentile chart when replotting it (e.g. carry those over from the previous version if the replot reinstates something).

In addition, if no changes to the axis ranges in the top chart occur (e.g. when the only reason for replotting the top chart is a change in labels), avoid resetting the axis ranges in the bottom chart (keep them as they were before the top chart replot), [or maybe just avoid replotting the bottom chart in this situation, since nothing that affects it has changed].