SplitButton
Pairs one action with a menu of related ones, for when a second action matters enough that burying it in a DropdownMenu would hide it. Both halves are ordinary Buttons, so they must share a variant, colour and size — the group only joins their facing corners.
Usage
Examples
Variants
Every sanctioned pairing, and the reason the pair must match: outline buttons drop the gap and overlap their borders into a single hairline, which only looks right when both halves carry the same variant.
Sizes
Both halves take the same size, since the group aligns them rather than sizing them.
Content
Text, icon-and-text, and icon-only leading halves. The trailing half stays a bare chevron — giving it a label doubles the width and makes the menu look like a second action.
With dropdown menu
The real shape: the leading half performs the default action, and only the chevron opens the menu. Repeat the default inside the menu only if its wording differs there.