Conversation inbox: single conversations cannot be selected by keyboard

[krallowski]

Description

Tabbing through the conversations page, I cannot select a single conversation to open via keyboard.

Steps to reproduce

1. Start multiple conversations
2. Press tab in order to reach another conversation in the inbox to open it

Expected behavior

I reach a single conversation via keyboard, it gets focused and pressing enter opens it

Current behavior

I cannot reach a single conversation, only the whole inbox as one block

Possible solution

Replace the div of the inbox entry with a button and style it accordingly with CSS:

mail/widgets/views/inboxMessagePreview.php

Line 21 in 7540f91

<?= Html::beginTag('div', $options) ?>

Additional info

I use Firefox and Humhub version 1.18