Hi tullio0106,
You can use a CSS variable for that purpose.
Example:

smart-drop-down-list {
	min-height: 35px;
	height: auto;
	width: 300px;
	--smart-drop-down-list-drop-down-height: 100px;
}

The –smart-drop-down-list-drop-down-height determines the height of the DropDownList’s dropdown.
Best regards,
Peter Stoev
Smart UI Team
https://www.htmlelements.com/