In May Power BI added the ability to show custom tool tips in reports. Which is very cool if you what you wanted displayed was already in a measure.
In most cases though you don’t want the count of a text column but rather the text of the text column. Such as the example below.
Turns out getting the Text to display isn’t terribly difficult, you just need to convert it to a measure.
To do this add a new measure to your table by clicking on Model> New Measure.
Then in the expression add something like the following two expressions:
Tootip = FIRSTNONBLANK('Table'[Name],TRUE)
Tooltip = TOPN(1, VALUES('Table'[Name]), [Name], ASC)
Of course it is likely will will want to construct something a little more sophisticated in which case CONCATENATEX works a treat!
Tooltip1 = CONCATENATEX('Table', [Name] & "" & [Date], ",")