How to select an invisible element in the chart
You can select any chart element for customization using the ribbon tab command or from the Format *** pane.
Using the ribbon tab
1. Select the chart to display the Chart Design and Format tabs:
2. On the Chart Format tab, in the Current Selection group, click the arrow of the Chart Elements dropdown list, then select the chart element you need.
If you need to open the Format *** pane to customize the selected element, click the Format Selection button in the Current Selection group:
Using the Format pane
1. Open the Format *** pane for any of the chart elements.
For example, right-click the chart plot area and select Format Plot Area... in the popup menu:
2. In the Format *** pane, click the arrow next to *** Options (Plot Area Options in this example) and choose the element you need to customize from the dropdown list: