Autocomplete slow to update with large data sets after material beta 12

Bug, feature request, or proposal:

When displaying an autocomplete list with a large number of options it is slow to display. It appears that this is caused by 2 event listeners being created for each item in the list. This slowness started after updating to beta 12.

You can see the large number of event listeners being set up if you open the Chrome dev tools and set the logging level to verbose. [Violation] Added non-passive event listener to a scroll-blocking 'touchstart' event. Consider marking event handler as 'passive' to make the page more responsive. See https://www.chromestatus.com/feature/5745543795965952

What is the expected behavior?

Similar performance when using autocomplete with 200+ data sets to older versions of material.

What is the current behavior?

Rendering an autocomplete with a large number of options has a delay, it is even longer when the dev tools are open due to the large number of event listeners being created causing logs to be written to the console

What are the steps to reproduce?

Open dev tools, set console logging to verbose and click the “Click to toggle autocomplete” button . You can also see the behavior by filtering the list, type anything to shorten the length of the list, then clear the input and new event listeners will be created again for each item in the list causing additional slowdown. https://plnkr.co/edit/QhlHy7FrlvQbDeRfncCo?p=preview

What is the use-case or motivation for changing an existing behavior?

Improve performance. Is it not possible to have a single event listener on the parent that catches click events that bubble up? If not do 2 event listeners need to be created for each item in the list?

Which versions of Angular, Material, OS, TypeScript, browsers are affected?

Angular: 4.4.4 Material: beta.12 All browsers

Is there anything else we should know?

Event handler times on beta.11 Clearing out the input box, causing all items to be displayed again [Violation] 'input' handler took 187ms Clicking the button to display the autocomplete [Violation] 'click' handler took 246ms

Event handler times on beta.12 doing the same actions [Violation] 'input' handler took 1347ms [Violation] 'click' handler took 1048ms

[radoslavpetranov]

I just spent 2 hours trying to figure out if I broke something performance-related somewhere after updating from material beta.8 to beta.12. I was comparing the performance between the app on prod and the newly updated dev version and my country autocomplete is definitely causing noticeable lag in beta.12.

I have some form arrays where each internal form object contains a country autocomplete (so a whole bunch of options) and adding a few of these autocompletes is making the page really slow.

I also see thousands upon thousands of these messages

[Violation] Added non-passive event listener to a scroll-blocking 'touchstart' event. Consider marking event handler as 'passive' to make the page more responsive. See https://www.chromestatus.com/feature/5745543795965952

[Swoox]

@mikeomeara1 cheers this solve the issues I had.