[PD] list item picker widget

[João Pais]

>> It's possible to build one with data structures. There may be one
>> from me or others on the pd forum. But it's really a pain to build.
> I'm not even so worried about the pain of building, but about how you
> can make something that feels good and intuitive to use given the
> limited HID data you get from Pd. I mean there is no way to detect
> hovering or a mouse key release. I made menu widgets that required the
> user to keep the mouse key pressed while dragging, thus scrolling
> through the list of available items to pick. Number boxes and sliders
> work also with dragging. Nowadays, I'm starting to believe that
> dragging with mouse key pressed is not an ergonomic action and I'm
> going to avoid it whenever possible. Both, [jp.menu] and
> [dropDownMenu], do the selection with two clicks. I think that is the
> better approach.

I think there's [mousestate] or maybe something in one of the iem 
libraries (?), and if I remember correctly, structs can declare if a 
mouse is over them. But yes, there are very few options, and a solution 
using the gui's own possibilities would surely be better.