I want to add a dropdown button which usually works as an expand / collapse button in a treegrid. I can't seem to find in the documentation how to add a button which is the exact width and height of the dropdown button, e.g. the specific (custom) button class. This dropdown button should be added to a cell component even if it cannot be expanded / collapsed. The outcome should be that the button in the circle should also be present in the place of the x marks.