Hello again, @Emma1,
This sounds like a perfect use case for graphlets, and for the Pie Chart preset in particular. I am going to use the "Big Class Families" sample data table in this example, and "Age" as if it was the "Month" category in your scenario.
Please try clicking on the background of your graph with the right mouse button (RMB) and navigate to the preset option in the "Hover Label" menu, like so:
By default, the pie chart created by this preset will:
* be filtered by both the X and Y values (as the baseline is a scatter plot, the marker is defined by both columns);
* use the next categorical column not yet used in your table for the pie chart X role;
* reuse the column assigned to the baseline graph for the Y role in the pie chart.
You likely don't want the pie chart filtered by the Y value of the scatter plot, as that would give you the values for a single point (it would be OK if this was a bar chart, which is filtered only by the X value by default). You can control which columns are used to filter the graphlet through the Hover Label Editor, at the bottom of that menu we just talked about. Go to the "filters" tab in the editor and select the columns you want to skip:
We now have an interesting looking pie chart in our hover label:
If you want to also change the X assignment of the pie chart, you can go back to the data table and set the "Next in Hierarchy" column property of the current X column (Month) to indicate what is the desired column to use. This will also work for future graphs.
If you want to change both the X and Y assignments of the hover label pie chart, your best bet is to create the pie chart you want in a separate Graph Builder window and save its definition to the clipboard using the "Save script" > "To Clipboard" Little Red Triangle menu option:
Now go back to your scatter plot and set this new graph as a graphlet using the "Paste Graphlet" option in the RMB hover label menu:
And now the hover label will use your custom pie chart as a template:
I hope this helps!
Cheers,
Nascif