Is it good or bad practice to repeat a split button's primary action? I've searched and didn't find anything definitive. I see it done both ways.
- A split button has a default action. Clicking "Insert" above performs a general "insert", but clicking on the split part opens a menu of related actions. The Zoom menu below is on a split button - clicking Stop Video performs the default action, and the split menu has several video-related actions.
- A non-split button just opens the menu. It doesn't perform an action when you click on it. That's why you might see the label twice.
When should you use a split button? From the Nielsen-Norman article linked above:
Split buttons are for presenting several related tools if one option is used most frequently. Making the most commonly accessed option a default lowers the interaction cost to use that option since it removes the need to open the menu before selecting the item.