Improve credit role multiselect.

[josiah-wolf-oberholtzer]

The current widget is both slow and makes examining what roles are selected difficult.

Consider switching to Select2 instead.

Pros:

• Much faster.
• All selected roles are always visible.

Cons:

• Potentially more greedy in terms of screen space.

@delucis thoughts?

[delucis]

Select2 could potentially be a big improvement.

Accommodations needed

• Only permits the selection of child nodes, not supercategories.
  Some quick stackoverflowing suggests this may be hackable if using ≤3.5.2, but not with the most recent 4.0.0
• Screen space can be easily managed.
  Applying the following CSS to the <ul> in the first Multiple select boxes example here, seems to successfully restrict its height (such that it could potentially fit into disco/graph’s bottom bar) & enable scrolling to see all selected items.

ul {
    overflow: scroll;
    height: 30px;
}

Alternative?

http://travistidwell.com/jquery.treeselect.js/

The example seems to run fairly quickly with a large, multi-level list (4096 items). Searching currently is only triggered by the search button, not while typing, but that ought to be a fairly straight-forward change.

Might also need some more skinning? Happy to volunteer some CSS-ing if needed.