Element unresponsive in quiet rooms when status changes are hidden

[grisu48]

Description

The Element Web UI and Desktop Application become unresponsive when displaying a very quiet room with disabled status changes, i.e.:

• Disabled: Show join/leave messages (invites/kicks/bans unaffected)
• Disabled: Show avatar changes
• Disabled: Show display name changes

In a quiet room, i.e. a room with almost no text messages but plenty of those status messages (join/leave, avatar changes, display name changes) Element becomes unresponsive/hangs itself, when the above mentioned preferences are applied. In my case the affected room is #dendrite-alerts:matrix.org but I notice a noticeable slowdown also on other rooms with those settings in place.

Here is a screenshot of how the room typically looks.

Steps to reproduce

• Join #dendrite-alerts:matrix.org
• Disable: Show join/leave messages (invites/kicks/bans unaffected)
• Disable: Show avatar changes
• Disable: Show display name changes
• Go another room, then go back to the affected room

Describe how what happens differs from what you expected.

Logs being sent: yes

Version information

• Platform: web (in-browser) and desktop

For the web app:

• Browser: Firefox 78 and 88
• OS: openSUSE Leap 15.2 and openSUSE Tumbleweed
• URL: app.element.io

For the desktop app:

• OS: openSUSE Leap and Tumbleweed
• Version: 1.7.26, olm 3.2.1 (current version from flathub.org)

[t3chguy]

Duplicate of https://github.com/vector-im/element-web/issues/7015