Dashboard has plans to implement a split button design as it would provide both a preferred, single-click call-to-action and a secondary menu with links to other panel building tools. This could presumably be achieved using existing buttons (certainly as separate buttons altogether), but it's a common pattern that I suspect other teams may find useful as well.

In the case of Dashboard, the main/left section of the 'Add panel' button would open Lens, directly. The arrow/right section would open a context menu, like so:

Additional considerations...

• The example shows the filled style, but I supposed this would need to be available in the hollow/outlined version as well
• I presume the 'extra actions' button will only ever be on the right
• Is this a new component or is there some way to sort of smush buttons together via props?
• Ultimately ths may get used in the stacked header nav, not sure what if any complications that presents