private boolean useUnitedRoundedSelection( boolean vertical, boolean horizontal ) {
		return selectionArc > 0 &&
			(selectionInsets == null ||
			 (vertical && selectionInsets.top == 0 && selectionInsets.bottom == 0) ||
			 (horizontal && selectionInsets.left == 0 && selectionInsets.right == 0));
	}
Paints (rounded) cell selection.
Supports {@link #selectionArc} and {@link #selectionInsets}.
<p>
<b>Note:</b> This method is only invoked if either selection arc
             is greater than zero or if selection insets are not empty.

@since 3
flatlaf-core/src/main/java/com/formdev/flatlaf/ui/FlatListUI.java