Dropdown separator line

I would like to create a drop-down combo box where various groups of items are divided by a separator line, exactly like as can be done in a standard menu control.  Is that possible with any TMS controls?  I've looked at AdvHTMLComboBox (adding a <hr> tag to a caption) but I don't like the fact that the html formatting shows up in the box when selected.  I didn't see any obvious way to do this using AdvSmoothComboBox either.

You could use a TAdvControlDropDown and as dropdown control select a TSectionListBox.

I've been experimenting with this idea and I've noticed something unexpected.  The arrow keys are generating the OnClick event.  Is that what it is supposed to do?  I was trying to make it so that the dropdown would be hidden after a single click on an item, but this behavior interferes with using the arrow keys to move up/down in the list.

This is by design. You’ll notice exactly the same
behavior in a regular VCL TListBox.