[mat-tree] Keyboard Interaction recommended by WAI-ARIA

Bug, feature request, or proposal:

Feature request

What is the expected behavior?

Read expected behavior under “Keyboard interactions” at w3.org/TR/wai-aria-practices/#TreeView. Should use TAB to focus [mat-tree] and use arrows to navigate. Similar to radio button behaviour.

What is the current behavior?

TAB and SHIFT + TAB to navigate. SPACE or ENTER to open/close a node.

What are the steps to reproduce?

Look at the example here: w3.org/TR/wai-aria-practices/examples/treeview/treeview-1/treeview-1a.html

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

To make [mat-tree] more usable and accessible. Especially important when having lots of items in a tree.

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

@angular: 6.1.4 @angular/material: 6.4.6 OS: Windows 10 Chrome: 69.0.3497.81 Typescript: 2.7.2

Is there anything else we should know?

No

[angular-robot[bot]]

Just a heads up that we kicked off a community voting process for your feature request. There are 20 days until the voting process ends.

Find more details about Angular’s feature request process in our documentation.

[angular-robot[bot]]

Thank you for submitting your feature request! Looks like during the polling process it didn’t collect a sufficient number of votes to move to the next stage.

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You can find more details about the feature request process in our documentation.