select(header): closes when filter input is focused

[Axeldorf]

Bug

Demo and steps to reproduce the issue

Demo URL (required)*:
With AngularJS Material Design v1.1.21: https://codepen.io/Axeldorf/pen/ExPGOpM
With AngularJS Material Design v1.1.24: https://codepen.io/Axeldorf/pen/yLeGQez

Detailed Reproduction Steps

1. Open selector.
2. Click on filter input

Explain the expected behavior

On focusing filter input, select element is not closed and user can write any filter.

Explain the current behavior

On focusing filter input, select element is closed and user can't write any filter.

Discuss the use-case or motivation for changing the existing behavior

User wants to filter options in select, so when user clicks on input to write select must be opened.

List the affected versions of AngularJS, Material, OS, and browsers

• AngularJS: 1.7.8
• AngularJS Material: 1.1.21 (works), 1.1.22+ (doesn't work)
• OS: Ubuntu 18.04
• Browsers: Chrome.

[Splaktar]

Thank you for this report.

This doesn't happen in the select header demo because it uses multiple.

I've identified the issue and will open a PR soon.