Impress chart data

To edit a chart
Double-click a chart to enter the chart edit mode:
Chart data values (for charts with own data).

I have a impress chart that was originally a Microsoft powerpoint chart. Prior to yesterday, I have been able to edit and add data to the chart by performing the steps above. This no longer works. When I double click the chart, a blank Calc sheet opens. No data. I have many years of data charted but do not have a way to get to the data.

Can you help?

I am using the latest version of LibreOffice Version: