Preload button mask images (invisible retry button)

[dbkr]

Steps to reproduce

1. Load element in browser
2. Go to room
3. Unplug Internet
4. Type a message & press enter
5. Wait for red '!' to appear by the message
6. Hover over message to get the action bar

Outcome

What did you expect?

An action bar with some action button, including retry

What happened instead?

Action bar with some or all buttons blank

We rely on loading the mask images for the buttons on-demand, which is particularly unfortunate for the retry button which tends to appear when you have no Internet.

Operating system

No response

Browser information

No response

URL for webapp

No response

Application version

No response

Homeserver

No response

Will you send logs?

No