I have charts on sheets in Excel with only partial data; e.g., category axis for months of the year but data only for March-August. I don't want the plotted line/area to rise from zero when the data begins and fall back to zero when the data ends. So I click on Tools Options Chart and select Plot empty cells as "not plotted (leave gaps)". But nothing changes on my chart, both for line graphs and area graphs. What am I doing wrong?