Widget is extremely slow

[argus231]

We migrated 80k tags. As soon as the widget is used, the edit or add mode is 10 seconds slower.
The widget cannot handle a lot of data.
Can that be changed somehow?

[qzminski]

I think that could be done by introducing a new customer route and telling widget to use it using the load callback: https://github.com/selectize/selectize.js/blob/master/docs/usage.md#callbacks

Pull requests are welcome as I am currently unable to work on it.