SelectBox Too Slow With Thousands of Options

[David Sanders]

There's several tickets and patches over the years regarding this, but nothing has come of it, and it's still slow after 9 (!) years. The last ticket I can find that made meaningful progress on it was #3202 which itself was closed in preference of #15220 rewriting it to jQuery 5 years ago, which had some work as recently as 9 months ago but then teetered out.

IMO this issue shouldn't continue to be kicked down the road, and a patch should be accepted for improved performance even if it doesn't close #15220. It's not an easy problem for third-party apps to address and when it gets slow it gets too slow to function.

I'm providing a pull request with changes that greatly improved performance in my testing with 20,000 items. It's still laggy but that's to be expected, and the goal here isn't to make it smooth as butter, but functionally useable for users.

[Tim Graham <timograham@…>]

In fb68674e:

Fixed #26561 -- Improved admin's JavaScript SelectBox performance on large lists.