I swear I answered this question in another thread, but you just need to add an extra column with any data in it (just re-use some attribute already in the grid elsewhere), then use the DataGridExtension to target that column. The widget will convert the column data into the button.
I think this can be supported. By the look of the widget pictures it can be done.
https://appstore.mendix.com/file?target=internal&guid=5348024557513907