yes it is possible but you need to play bit different in this scenario. normally tooltip works based on row... for your data and scenario of master/detail or parent or child you need to create one additional sheet where it will display only related incident details details. in mouse hover action of incident you need to add filter so that the other sheet will display only that incident details. and the main tip and technique here is when you place your mouse in that incident it should display other sheet where it is displaying subsequent details of your incident... for this in toolTip you have option called insert sheet . with that insert sheet you need to add your detailed additional sheet which you created for other purpose. hope this will give you the exact result which you require to display the data in tool tip. this is the workaround for the logic which you requested. if you agree my option you can click on helpful or correct answer so that i also will become famous by giving answers to those who are in real need of problems... I am calculations expert in tableau... especially with functions.... Best of Luck...
Created a New sheet with following 5 fields (all in rows)
Incident#/CA#/Short Desc/CA status/Due date
Worksheet->Actions->Hover->Source sheet(New Sheet)-->Target Sheets(Old sheet)-->All new fields in New Sheet selected.
Then I went to My old sheet and Worksheet-->ToolTip-->Insert New sheet (Sheet name "New Sheet") and then on mouse hover it displays all my previous tooltip contents + just the sheet name "New Sheet".
Am I doing something wrong. Can you kindly show some screenshot to address any misunderstandings.